From: John Darrington <john@darrington.wattle.id.au>
Date: Fri, 31 Dec 2004 08:51:06 +0000 (+0000)
Subject: Added Boxplots to the EXAMINE subcommand repertoire
X-Git-Tag: v0.4.0~209
X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=46cc6dd316280579f5b03dfd39d01bc7daf88df7;p=pspp-builds.git

Added Boxplots to the EXAMINE subcommand repertoire
Fixed  a few bugs in percentiles calculations
---

diff --git a/doc/statistics.texi b/doc/statistics.texi
index 56c37949..98be7cc7 100644
--- a/doc/statistics.texi
+++ b/doc/statistics.texi
@@ -259,6 +259,15 @@ how many upper and lower extremes to show.  The default number is 5.
 
 The PLOT subcommand specifies which plots are to be produced if any.
 
+The COMPARE subcommand is only relevant if producing boxplots, and it is only 
+useful there is more than one dependent variable and at least one factor.   If 
+/COMPARE=GROUPS is specified, then one plot per dependent variable is produced,
+containing boxplots for all the factors.
+If /COMPARE=VARIABLES is specified, then one plot per factor is produced, each 
+each containing one boxplot per dependent variable.
+If the /COMPARE subcommand is ommitted, then PSPP uses the default value of 
+/COMPARE=GROUPS.
+
 The CINTERVAL subcommand specifies the confidence interval to use in
 calculation of the descriptives command.  The default it 95%.
 
diff --git a/po/en_GB.po b/po/en_GB.po
index 6b382054..9dec07c7 100644
--- a/po/en_GB.po
+++ b/po/en_GB.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PSPP 0.3.1\n"
 "Report-Msgid-Bugs-To: pspp-dev@gnu.org\n"
-"POT-Creation-Date: 2004-12-29 08:18+0800\n"
+"POT-Creation-Date: 2004-12-31 08:53+0800\n"
 "PO-Revision-Date: 2004-01-23 13:04+0800\n"
 "Last-Translator: John Darrington <john@darrington.wattle.id.au>\n"
 "Language-Team: John Darrington <john@darrington.wattle.id.au>\n"
@@ -957,7 +957,7 @@ msgstr ""
 msgid "Only USE ALL is currently implemented."
 msgstr ""
 
-#: src/descript.c:99 src/examine.q:1400 src/frequencies.q:112 src/oneway.q:396
+#: src/descript.c:99 src/examine.q:1420 src/frequencies.q:112 src/oneway.q:396
 #: src/t-test.q:690 src/t-test.q:713 src/t-test.q:836 src/t-test.q:1173
 msgid "Mean"
 msgstr ""
@@ -970,11 +970,11 @@ msgstr ""
 msgid "Std Dev"
 msgstr ""
 
-#: src/descript.c:102 src/examine.q:1478 src/frequencies.q:117
+#: src/descript.c:102 src/examine.q:1498 src/frequencies.q:117
 msgid "Variance"
 msgstr ""
 
-#: src/descript.c:103 src/examine.q:1585 src/frequencies.q:118
+#: src/descript.c:103 src/examine.q:1605 src/frequencies.q:118
 msgid "Kurtosis"
 msgstr ""
 
@@ -982,7 +982,7 @@ msgstr ""
 msgid "S E Kurt"
 msgstr ""
 
-#: src/descript.c:105 src/examine.q:1565 src/frequencies.q:120
+#: src/descript.c:105 src/examine.q:1585 src/frequencies.q:120
 msgid "Skewness"
 msgstr ""
 
@@ -990,16 +990,16 @@ msgstr ""
 msgid "S E Skew"
 msgstr ""
 
-#: src/descript.c:107 src/examine.q:1526 src/frequencies.q:122
+#: src/descript.c:107 src/examine.q:1546 src/frequencies.q:122
 msgid "Range"
 msgstr ""
 
-#: src/descript.c:108 src/examine.q:1503 src/frequencies.q:123
+#: src/descript.c:108 src/examine.q:1523 src/frequencies.q:123
 #: src/oneway.q:408
 msgid "Minimum"
 msgstr ""
 
-#: src/descript.c:109 src/examine.q:1514 src/frequencies.q:124
+#: src/descript.c:109 src/examine.q:1534 src/frequencies.q:124
 #: src/oneway.q:409
 msgid "Maximum"
 msgstr ""
@@ -3723,7 +3723,7 @@ msgstr ""
 
 #: src/sysfile-info.c:531 src/vfm.c:875 src/crosstabs.q:1099
 #: src/crosstabs.q:1126 src/crosstabs.q:1146 src/crosstabs.q:1168
-#: src/examine.q:1054 src/frequencies.q:1136 src/frequencies.q:1257
+#: src/examine.q:1074 src/frequencies.q:1136 src/frequencies.q:1257
 msgid "Value"
 msgstr ""
 
@@ -3944,32 +3944,32 @@ msgstr ""
 msgid "Summary."
 msgstr ""
 
-#: src/crosstabs.q:802 src/examine.q:838
+#: src/crosstabs.q:802 src/examine.q:858
 msgid "Cases"
 msgstr ""
 
-#: src/crosstabs.q:803 src/examine.q:772 src/frequencies.q:1134
+#: src/crosstabs.q:803 src/examine.q:792 src/frequencies.q:1134
 #: src/frequencies.q:1507
 msgid "Valid"
 msgstr ""
 
-#: src/crosstabs.q:804 src/examine.q:773 src/frequencies.q:1202
+#: src/crosstabs.q:804 src/examine.q:793 src/frequencies.q:1202
 #: src/frequencies.q:1508
 msgid "Missing"
 msgstr ""
 
 #: src/crosstabs.q:805 src/crosstabs.q:1008 src/crosstabs.q:1722
-#: src/examine.q:774 src/frequencies.q:1211 src/oneway.q:307 src/oneway.q:486
+#: src/examine.q:794 src/frequencies.q:1211 src/oneway.q:307 src/oneway.q:486
 msgid "Total"
 msgstr ""
 
-#: src/crosstabs.q:815 src/examine.q:850 src/frequencies.q:1506
+#: src/crosstabs.q:815 src/examine.q:870 src/frequencies.q:1506
 #: src/oneway.q:395 src/t-test.q:689 src/t-test.q:712 src/t-test.q:837
 #: src/t-test.q:1372
 msgid "N"
 msgstr ""
 
-#: src/crosstabs.q:816 src/examine.q:853 src/frequencies.q:1138
+#: src/crosstabs.q:816 src/examine.q:873 src/frequencies.q:1138
 #: src/frequencies.q:1139 src/frequencies.q:1140
 msgid "Percent"
 msgstr ""
@@ -4007,7 +4007,7 @@ msgid "adj. resid."
 msgstr ""
 
 #: src/crosstabs.q:1098 src/crosstabs.q:1125 src/crosstabs.q:1145
-#: src/crosstabs.q:1166 src/examine.q:1288
+#: src/crosstabs.q:1166 src/examine.q:1308
 msgid "Statistic"
 msgstr ""
 
@@ -4190,96 +4190,105 @@ msgstr ""
 msgid "%s Dependent"
 msgstr ""
 
-#: src/examine.q:418 src/examine.q:430
+#: src/examine.q:438 src/examine.q:450
 #, c-format
 msgid "%s and %s are mutually exclusive"
 msgstr ""
 
-#: src/examine.q:832
+#: src/examine.q:852
 msgid "Case Processing Summary"
 msgstr ""
 
-#: src/examine.q:1038
+#: src/examine.q:1058
 msgid "Extreme Values"
 msgstr ""
 
-#: src/examine.q:1055
+#: src/examine.q:1075
 msgid "Case Number"
 msgstr ""
 
-#: src/examine.q:1143
+#: src/examine.q:1163
 msgid "Highest"
 msgstr ""
 
-#: src/examine.q:1148
+#: src/examine.q:1168
 msgid "Lowest"
 msgstr ""
 
-#: src/examine.q:1289 src/oneway.q:398 src/oneway.q:705
+#: src/examine.q:1309 src/oneway.q:398 src/oneway.q:705
 msgid "Std. Error"
 msgstr ""
 
-#: src/examine.q:1291 src/oneway.q:412
+#: src/examine.q:1311 src/oneway.q:412
 msgid "Descriptives"
 msgstr ""
 
-#: src/examine.q:1418 src/oneway.q:403
+#: src/examine.q:1438 src/oneway.q:403
 #, c-format
 msgid "%g%% Confidence Interval for Mean"
 msgstr ""
 
-#: src/examine.q:1424 src/oneway.q:405
+#: src/examine.q:1444 src/oneway.q:405
 msgid "Lower Bound"
 msgstr ""
 
-#: src/examine.q:1435 src/oneway.q:406
+#: src/examine.q:1455 src/oneway.q:406
 msgid "Upper Bound"
 msgstr ""
 
-#: src/examine.q:1447
+#: src/examine.q:1467
 msgid "5% Trimmed Mean"
 msgstr ""
 
-#: src/examine.q:1458 src/frequencies.q:114
+#: src/examine.q:1478 src/frequencies.q:114
 msgid "Median"
 msgstr ""
 
-#: src/examine.q:1490 src/oneway.q:397 src/t-test.q:691 src/t-test.q:714
+#: src/examine.q:1510 src/oneway.q:397 src/t-test.q:691 src/t-test.q:714
 #: src/t-test.q:838 src/t-test.q:1174
 msgid "Std. Deviation"
 msgstr ""
 
-#: src/examine.q:1538
+#: src/examine.q:1558
 msgid "Interquartile Range"
 msgstr ""
 
-#: src/examine.q:1628
+#: src/examine.q:1708
+#, c-format
+msgid "Boxplot of %s"
+msgstr ""
+
+#: src/examine.q:1734
+msgid "Boxplot"
+msgstr ""
+
+#: src/examine.q:1773
 #, c-format
 msgid "Normal Q-Q Plot of %s"
 msgstr ""
 
-#: src/examine.q:1629 src/examine.q:1635
+#: src/examine.q:1774 src/examine.q:1780
 msgid "Observed Value"
 msgstr ""
 
-#: src/examine.q:1630
+#: src/examine.q:1775
 msgid "Expected Normal"
 msgstr ""
 
-#: src/examine.q:1633
+#: src/examine.q:1778
 #, c-format
 msgid "Detrended Normal Q-Q Plot of %s"
 msgstr ""
 
-#: src/examine.q:1636
+#: src/examine.q:1781
 msgid "Dev from Normal"
 msgstr ""
 
-#: src/examine.q:1757 src/examine.q:1779 src/frequencies.q:1518
+#: src/examine.q:1902 src/examine.q:1924 src/frequencies.q:1518
 msgid "Percentiles"
 msgstr ""
 
-#: src/examine.q:1904
+#: src/examine.q:2049
 msgid "Tukey's Hinges"
 msgstr ""
 
diff --git a/po/pspp.pot b/po/pspp.pot
index c3fbf686..087dba18 100644
--- a/po/pspp.pot
+++ b/po/pspp.pot
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: pspp-dev@gnu.org\n"
-"POT-Creation-Date: 2004-12-29 08:18+0800\n"
+"POT-Creation-Date: 2004-12-31 08:53+0800\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -958,7 +958,7 @@ msgstr ""
 msgid "Only USE ALL is currently implemented."
 msgstr ""
 
-#: src/descript.c:99 src/examine.q:1400 src/frequencies.q:112 src/oneway.q:396
+#: src/descript.c:99 src/examine.q:1420 src/frequencies.q:112 src/oneway.q:396
 #: src/t-test.q:690 src/t-test.q:713 src/t-test.q:836 src/t-test.q:1173
 msgid "Mean"
 msgstr ""
@@ -971,11 +971,11 @@ msgstr ""
 msgid "Std Dev"
 msgstr ""
 
-#: src/descript.c:102 src/examine.q:1478 src/frequencies.q:117
+#: src/descript.c:102 src/examine.q:1498 src/frequencies.q:117
 msgid "Variance"
 msgstr ""
 
-#: src/descript.c:103 src/examine.q:1585 src/frequencies.q:118
+#: src/descript.c:103 src/examine.q:1605 src/frequencies.q:118
 msgid "Kurtosis"
 msgstr ""
 
@@ -983,7 +983,7 @@ msgstr ""
 msgid "S E Kurt"
 msgstr ""
 
-#: src/descript.c:105 src/examine.q:1565 src/frequencies.q:120
+#: src/descript.c:105 src/examine.q:1585 src/frequencies.q:120
 msgid "Skewness"
 msgstr ""
 
@@ -991,16 +991,16 @@ msgstr ""
 msgid "S E Skew"
 msgstr ""
 
-#: src/descript.c:107 src/examine.q:1526 src/frequencies.q:122
+#: src/descript.c:107 src/examine.q:1546 src/frequencies.q:122
 msgid "Range"
 msgstr ""
 
-#: src/descript.c:108 src/examine.q:1503 src/frequencies.q:123
+#: src/descript.c:108 src/examine.q:1523 src/frequencies.q:123
 #: src/oneway.q:408
 msgid "Minimum"
 msgstr ""
 
-#: src/descript.c:109 src/examine.q:1514 src/frequencies.q:124
+#: src/descript.c:109 src/examine.q:1534 src/frequencies.q:124
 #: src/oneway.q:409
 msgid "Maximum"
 msgstr ""
@@ -3723,7 +3723,7 @@ msgstr ""
 
 #: src/sysfile-info.c:531 src/vfm.c:875 src/crosstabs.q:1099
 #: src/crosstabs.q:1126 src/crosstabs.q:1146 src/crosstabs.q:1168
-#: src/examine.q:1054 src/frequencies.q:1136 src/frequencies.q:1257
+#: src/examine.q:1074 src/frequencies.q:1136 src/frequencies.q:1257
 msgid "Value"
 msgstr ""
 
@@ -3944,32 +3944,32 @@ msgstr ""
 msgid "Summary."
 msgstr ""
 
-#: src/crosstabs.q:802 src/examine.q:838
+#: src/crosstabs.q:802 src/examine.q:858
 msgid "Cases"
 msgstr ""
 
-#: src/crosstabs.q:803 src/examine.q:772 src/frequencies.q:1134
+#: src/crosstabs.q:803 src/examine.q:792 src/frequencies.q:1134
 #: src/frequencies.q:1507
 msgid "Valid"
 msgstr ""
 
-#: src/crosstabs.q:804 src/examine.q:773 src/frequencies.q:1202
+#: src/crosstabs.q:804 src/examine.q:793 src/frequencies.q:1202
 #: src/frequencies.q:1508
 msgid "Missing"
 msgstr ""
 
 #: src/crosstabs.q:805 src/crosstabs.q:1008 src/crosstabs.q:1722
-#: src/examine.q:774 src/frequencies.q:1211 src/oneway.q:307 src/oneway.q:486
+#: src/examine.q:794 src/frequencies.q:1211 src/oneway.q:307 src/oneway.q:486
 msgid "Total"
 msgstr ""
 
-#: src/crosstabs.q:815 src/examine.q:850 src/frequencies.q:1506
+#: src/crosstabs.q:815 src/examine.q:870 src/frequencies.q:1506
 #: src/oneway.q:395 src/t-test.q:689 src/t-test.q:712 src/t-test.q:837
 #: src/t-test.q:1372
 msgid "N"
 msgstr ""
 
-#: src/crosstabs.q:816 src/examine.q:853 src/frequencies.q:1138
+#: src/crosstabs.q:816 src/examine.q:873 src/frequencies.q:1138
 #: src/frequencies.q:1139 src/frequencies.q:1140
 msgid "Percent"
 msgstr ""
@@ -4007,7 +4007,7 @@ msgid "adj. resid."
 msgstr ""
 
 #: src/crosstabs.q:1098 src/crosstabs.q:1125 src/crosstabs.q:1145
-#: src/crosstabs.q:1166 src/examine.q:1288
+#: src/crosstabs.q:1166 src/examine.q:1308
 msgid "Statistic"
 msgstr ""
 
@@ -4190,96 +4190,105 @@ msgstr ""
 msgid "%s Dependent"
 msgstr ""
 
-#: src/examine.q:418 src/examine.q:430
+#: src/examine.q:438 src/examine.q:450
 #, c-format
 msgid "%s and %s are mutually exclusive"
 msgstr ""
 
-#: src/examine.q:832
+#: src/examine.q:852
 msgid "Case Processing Summary"
 msgstr ""
 
-#: src/examine.q:1038
+#: src/examine.q:1058
 msgid "Extreme Values"
 msgstr ""
 
-#: src/examine.q:1055
+#: src/examine.q:1075
 msgid "Case Number"
 msgstr ""
 
-#: src/examine.q:1143
+#: src/examine.q:1163
 msgid "Highest"
 msgstr ""
 
-#: src/examine.q:1148
+#: src/examine.q:1168
 msgid "Lowest"
 msgstr ""
 
-#: src/examine.q:1289 src/oneway.q:398 src/oneway.q:705
+#: src/examine.q:1309 src/oneway.q:398 src/oneway.q:705
 msgid "Std. Error"
 msgstr ""
 
-#: src/examine.q:1291 src/oneway.q:412
+#: src/examine.q:1311 src/oneway.q:412
 msgid "Descriptives"
 msgstr ""
 
-#: src/examine.q:1418 src/oneway.q:403
+#: src/examine.q:1438 src/oneway.q:403
 #, c-format
 msgid "%g%% Confidence Interval for Mean"
 msgstr ""
 
-#: src/examine.q:1424 src/oneway.q:405
+#: src/examine.q:1444 src/oneway.q:405
 msgid "Lower Bound"
 msgstr ""
 
-#: src/examine.q:1435 src/oneway.q:406
+#: src/examine.q:1455 src/oneway.q:406
 msgid "Upper Bound"
 msgstr ""
 
-#: src/examine.q:1447
+#: src/examine.q:1467
 msgid "5% Trimmed Mean"
 msgstr ""
 
-#: src/examine.q:1458 src/frequencies.q:114
+#: src/examine.q:1478 src/frequencies.q:114
 msgid "Median"
 msgstr ""
 
-#: src/examine.q:1490 src/oneway.q:397 src/t-test.q:691 src/t-test.q:714
+#: src/examine.q:1510 src/oneway.q:397 src/t-test.q:691 src/t-test.q:714
 #: src/t-test.q:838 src/t-test.q:1174
 msgid "Std. Deviation"
 msgstr ""
 
-#: src/examine.q:1538
+#: src/examine.q:1558
 msgid "Interquartile Range"
 msgstr ""
 
-#: src/examine.q:1628
+#: src/examine.q:1708
+#, c-format
+msgid "Boxplot of %s"
+msgstr ""
+
+#: src/examine.q:1734
+msgid "Boxplot"
+msgstr ""
+
+#: src/examine.q:1773
 #, c-format
 msgid "Normal Q-Q Plot of %s"
 msgstr ""
 
-#: src/examine.q:1629 src/examine.q:1635
+#: src/examine.q:1774 src/examine.q:1780
 msgid "Observed Value"
 msgstr ""
 
-#: src/examine.q:1630
+#: src/examine.q:1775
 msgid "Expected Normal"
 msgstr ""
 
-#: src/examine.q:1633
+#: src/examine.q:1778
 #, c-format
 msgid "Detrended Normal Q-Q Plot of %s"
 msgstr ""
 
-#: src/examine.q:1636
+#: src/examine.q:1781
 msgid "Dev from Normal"
 msgstr ""
 
-#: src/examine.q:1757 src/examine.q:1779 src/frequencies.q:1518
+#: src/examine.q:1902 src/examine.q:1924 src/frequencies.q:1518
 msgid "Percentiles"
 msgstr ""
 
-#: src/examine.q:1904
+#: src/examine.q:2049
 msgid "Tukey's Hinges"
 msgstr ""
 
diff --git a/src/ChangeLog b/src/ChangeLog
index b2ec7335..544f91a4 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,10 @@
+Fri Dec 31 16:47:45 WST 2004 John Darrington <john@darrington.wattle.id.au>
+
+	* examine.q box-whisker.c chart.h Implemented boxplots in EXAMINE
+
+	* percentiles.c Fixed some bugs when calculating percentiles when
+	there's a small number of cases.
+
 Wed Dec 29 08:18:08 WST 2004 John Darrington <john@darrington.wattle.id.au>
 
 	* percentiles.[ch] Added. Calculates percentiles and Tukey hinges
diff --git a/src/box-whisker.c b/src/box-whisker.c
index fa52476e..2600e8aa 100644
--- a/src/box-whisker.c
+++ b/src/box-whisker.c
@@ -20,106 +20,77 @@
 
 #include "chart.h"
 #include <math.h>
+#include "misc.h"
 
-/* Draw a box-and-whiskers plot
-*/
-
-struct data_stats 
-{
-  double ptile0  ;
-  double ptile25 ;
-  double median  ;
-  double ptile75 ;
-
-  double ptile100;
-
-  double outlier ;
-};
-
-
-const struct data_stats stats1 = {
-  40,
-  45,
-  54,
-  60,
-  70,
-
-  33
-};
-
-const struct data_stats stats2 = {
-  30,
-  40,
-  45,
-  54,
-  60,
-
-
-  72
-};
-
-
-
-
-
-static const double y_min = 25;
-static const double y_max = 75;
-static const double y_tick = 10;
+#include "factor_stats.h"
 
 
+/* Draw a box-and-whiskers plot
+*/
 
-#define min(A,B) ((A>B)?B:A)
-
-
-void draw_box_and_whiskers(struct chart *ch,
-			   double box_centre, const struct data_stats *s, 
-			   const char *name);
-
+/* Draw an outlier on the plot CH
+ * at CENTRELINE
+ * The outlier is in (*wvp)[idx]
+ * If EXTREME is non zero, then consider it to be an extreme
+ * value
+ */
+void 
+draw_outlier(struct chart *ch, double centreline, 
+	     struct weighted_value **wvp, 
+	     int idx,
+	     short extreme);
 
-static double ordinate_scale;
 
-void
-draw_box_whisker_chart(struct chart *ch, const char *title)
+void 
+draw_outlier(struct chart *ch, double centreline, 
+	     struct weighted_value **wvp, 
+	     int idx,
+	     short extreme
+	     )
 {
-  double d;
+  char label[10];
 
-  ordinate_scale = fabs(ch->data_top -  ch->data_bottom) / fabs(y_max - y_min) ;
+#define MARKER_CIRCLE 4
+#define MARKER_STAR 3
 
+  pl_fmarker_r(ch->lp,
+	       centreline,
+	       ch->data_bottom + 
+	       (wvp[idx]->v.f - ch->y_min ) * ch->ordinate_scale,
+	       extreme?MARKER_STAR:MARKER_CIRCLE,
+	       20);
 
-  chart_write_title(ch, title);
+  pl_moverel_r(ch->lp, 10,0);
 
+  snprintf(label, 10, "%d", wvp[idx]->case_nos->num);
   
-
-  /* Move to data bottom-left */
-  pl_move_r(ch->lp, 
-		  ch->data_left, ch->data_bottom);
-
-  for ( d = y_min; d <= y_max ; d += y_tick )
-    {
-      draw_tick (ch, TICK_ORDINATE, (d - y_min ) * ordinate_scale, "%g", d);
-    }
-
-  draw_box_and_whiskers(ch,
-			ch->data_left  + 1.0/4.0 * (ch->data_right - ch->data_left) ,
-			&stats1,"Stats1"
-			);
-
-  draw_box_and_whiskers(ch,
-			ch->data_left + 3.0/4.0 * (ch->data_right - ch->data_left),
-			&stats2,"Stats2"
-			);
-
+  pl_alabel_r(ch->lp, 'l', 'c', label);
 
 }
 
 
 void 
-draw_box_and_whiskers(struct chart *ch,
-		      double box_centre, const struct data_stats *s,
-		      const char *name)
+boxplot_draw_boxplot(struct chart *ch,
+		     double box_centre, 
+		     double box_width,
+		     struct metrics *m,
+		     /* 
+		     const double hinge[3],
+		     struct weighted_value **wvp,
+		     int n_data,
+		     */
+		     const char *name)
 {
+  double whisker[2];
+  int i;
+
+
+  const double *hinge = m->hinge;
+  struct weighted_value **wvp = m->wvp;
+  const int n_data = m->n_data;
+
+  const double step = (hinge[2] - hinge[0]) * 1.5;
 
-  const double box_width = (ch->data_right - ch->data_left) / 4.0;
 
   const double box_left = box_centre - box_width / 2.0;
 
@@ -127,22 +98,32 @@ draw_box_and_whiskers(struct chart *ch,
 
 
   const double box_bottom = 
-    ch->data_bottom + ( s->ptile25 - y_min ) * ordinate_scale;
+    ch->data_bottom + ( hinge[0] - ch->y_min ) * ch->ordinate_scale;
 
 
   const double box_top = 
-    ch->data_bottom + ( s->ptile75 - y_min ) * ordinate_scale;
+    ch->data_bottom + ( hinge[2] - ch->y_min ) * ch->ordinate_scale;
 
+  whisker[1] = hinge[2];
+  whisker[0] = wvp[0]->v.f;
 
-  const double iq_range = s->ptile75 - s->ptile25;
+  for ( i = 0 ; i < n_data ; ++i ) 
+    {
+      if ( hinge[2] + step >  wvp[i]->v.f) 
+	whisker[1] = wvp[i]->v.f;
 
+      if ( hinge[0] - step >  wvp[i]->v.f) 
+	whisker[0] = wvp[i]->v.f;
+    
+    }
+    
+  
   const double bottom_whisker = 
-    ch->data_bottom + (min(s->ptile0,s->ptile25 + iq_range*1.5)  - y_min ) * 
-    ordinate_scale;
+    ch->data_bottom + ( whisker[0] - ch->y_min ) * ch->ordinate_scale;
+
+  const double top_whisker = 
+    ch->data_bottom + ( whisker[1] - ch->y_min ) * ch->ordinate_scale;
 
-  const double top_whisker =
-    ch->data_bottom + (min(s->ptile100,s->ptile75 + iq_range*1.5)  - y_min ) * 
-    ordinate_scale;
 	
   pl_savestate_r(ch->lp);
 
@@ -166,9 +147,9 @@ draw_box_and_whiskers(struct chart *ch,
   pl_linewidth_r(ch->lp,5);
   pl_fline_r(ch->lp, 
 	     box_left, 
-	     ch->data_bottom + ( s->median - y_min ) * ordinate_scale,
+	     ch->data_bottom + ( hinge[1] - ch->y_min ) * ch->ordinate_scale,
 	     box_right,   
-	     ch->data_bottom + ( s->median - y_min ) * ordinate_scale);
+	     ch->data_bottom + ( hinge[1] - ch->y_min ) * ch->ordinate_scale);
   pl_restorestate_r(ch->lp);
 
 
@@ -187,6 +168,7 @@ draw_box_and_whiskers(struct chart *ch,
 	     top_whisker);
 
 
+
   /* Draw centre line.
      (bottom half) */
   pl_fline_r(ch->lp, 
@@ -198,15 +180,19 @@ draw_box_and_whiskers(struct chart *ch,
 	     box_centre, top_whisker,
 	     box_centre, box_top);
 
-
-  /* Draw an outlier */
-  pl_fcircle_r(ch->lp,
-	       box_centre, 
-	       ch->data_bottom + (s->outlier - y_min ) * ordinate_scale,
-	       5);
-
-  pl_moverel_r(ch->lp, 10,0);
-  pl_alabel_r(ch->lp,'l','c',"123");
+  /* Draw outliers */
+  for ( i = 0 ; i < n_data ; ++i ) 
+    {
+      if ( wvp[i]->v.f >= hinge[2] + step ) 
+	draw_outlier(ch, box_centre, wvp, i, 
+		     ( wvp[i]->v.f > hinge[2] + 2 * step ) 
+		     );
+
+      if ( wvp[i]->v.f <= hinge[0] - step ) 
+	draw_outlier(ch, box_centre, wvp, i, 
+		     ( wvp[i]->v.f < hinge[0] - 2 * step )
+		     );
+    }
 
 
   /* Draw  tick  mark on x axis */
@@ -216,3 +202,34 @@ draw_box_and_whiskers(struct chart *ch,
 
 }
 
+
+
+void
+boxplot_draw_yscale(struct chart *ch , double y_max, double y_min)
+{
+  double y_tick;
+  double d;
+
+  ch->y_max  = y_max;
+  ch->y_min  = y_min;
+
+  y_tick = chart_rounded_tick(fabs(ch->y_max - ch->y_min) / 5.0);
+
+  ch->y_min = (ceil( ch->y_min  / y_tick ) - 1.0  ) * y_tick;
+      
+  ch->y_max = ( floor( ch->y_max  / y_tick ) + 1.0  ) * y_tick;
+
+  ch->ordinate_scale = fabs(ch->data_top - ch->data_bottom) 
+    / fabs(ch->y_max - ch->y_min) ;
+
+
+  /* Move to data bottom-left */
+  pl_move_r(ch->lp, 
+	    ch->data_left, ch->data_bottom);
+
+  for ( d = ch->y_min; d <= ch->y_max ; d += y_tick )
+    {
+      draw_tick (ch, TICK_ORDINATE, (d - ch->y_min ) * ch->ordinate_scale, "%g", d);
+    }
+
+}
diff --git a/src/chart.h b/src/chart.h
index f2c9e501..eec5bff5 100644
--- a/src/chart.h
+++ b/src/chart.h
@@ -61,7 +61,7 @@ struct chart {
 
   char fill_colour[10];
 
-  /* Stuff Particular to Cartesians */
+  /* Stuff Particular to Cartesians (and Boxplots ) */
   double ordinate_scale;
   double abscissa_scale;
   double x_min;
@@ -166,8 +166,18 @@ void chart_write_yscale(struct chart *ch,
 
 void chart_datum(struct chart *ch, int dataset, double x, double y);
 
+struct metrics;
 
 
+void  boxplot_draw_boxplot(struct chart *ch,
+			   double box_centre, 
+			   double box_width,
+			   struct metrics *m,
+			   const char *name);
+
+
+void boxplot_draw_yscale(struct chart *ch , double y_max, double y_min);
+
 
 enum CHART_DIM
   {
diff --git a/src/examine.q b/src/examine.q
index 97a63a90..5cb89af2 100644
--- a/src/examine.q
+++ b/src/examine.q
@@ -57,6 +57,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
    incl:include/!exclude;
    +compare=cmp:variables/!groups;
    +percentiles=custom;
+   +id=var;
    +plot[plt_]=stemleaf,boxplot,npplot,:spreadlevel(*d:n),histogram,all,none;
    +cinterval=double;
    +statistics[st_]=descriptives,:extreme(*d:n),all,none.
@@ -120,9 +121,22 @@ static void show_percentiles(struct variable **dependent_var,
 
 
 
+
 void np_plot(const struct metrics *m, const char *factorname);
 
 
+void box_plot_group(const struct factor *fctr, 
+		    const struct variable **vars, int n_vars,
+		    const struct variable *id
+		    ) ;
+
+
+void box_plot_variables(const struct factor *fctr, 
+			struct variable **vars, int n_vars, 
+			const struct variable *id
+			);
+
+
 
 /* Per Split function */
 static void run_examine(const struct casefile *cf, void *cmd_);
@@ -134,6 +148,22 @@ void factor_calc(struct ccase *c, int case_no,
 		 double weight, int case_missing);
 
 
+/* Represent a factor as a string, so it can be
+   printed in a human readable fashion */
+const char * factor_to_string(const struct factor *fctr, 
+			struct factor_statistics *fs,
+			const struct variable *var);
+
+
+/* Represent a factor as a string, so it can be
+   printed in a human readable fashion,
+   but sacrificing some readablility for the sake of brevity */
+const char *factor_to_string_concise(const struct factor *fctr, 
+				     struct factor_statistics *fs);
+
+
+
+
 /* Function to use for testing for missing values */
 static is_missing_func value_is_missing;
 
@@ -169,7 +199,6 @@ cmd_examine(void)
   if ( ! cmd.sbc_cinterval) 
     cmd.n_cinterval[0] = 95.0;
 
-
   /* If descriptives have been requested, make sure the 
      quartiles are calculated */
   if ( cmd.a_statistics[XMN_ST_DESCRIPTIVES] )
@@ -223,6 +252,18 @@ output_examine(void)
 		np_plot(&totals[v], var_to_string(dependent_vars[v]));
 	    }
 
+	  if ( cmd.a_plot[XMN_PLT_BOXPLOT] ) 
+	    {
+	      if ( cmd.cmp == XMN_GROUPS ) 
+		{
+		  box_plot_group(0, dependent_vars, n_dependent_vars, 
+				 cmd.v_id);
+		}
+	      else
+		box_plot_variables(0, dependent_vars, n_dependent_vars,
+				   cmd.v_id);
+	    }
+
 	  if ( cmd.a_plot[XMN_PLT_HISTOGRAM] ) 
 	    {
 	      for ( v = 0 ; v < n_dependent_vars; ++v ) 
@@ -269,39 +310,26 @@ output_examine(void)
 
 	  struct factor_statistics **fs = fctr->fs ;
 
+	  if ( cmd.a_plot[XMN_PLT_BOXPLOT] )
+	    {
+	      if ( cmd.cmp == XMN_VARIABLES ) 
+		box_plot_variables(fctr, dependent_vars, n_dependent_vars, 
+				   cmd.v_id);
+	      else
+		box_plot_group(fctr, dependent_vars, n_dependent_vars, 
+			       cmd.v_id);
+	    }
+
 	  for ( v = 0 ; v < n_dependent_vars; ++v )
 	    {
 
 	      for ( fs = fctr->fs ; *fs ; ++fs ) 
 		{
-		  char buf1[100];
-		  char buf2[100];
-		  sprintf(buf1, "%s (",
-			  var_to_string(dependent_vars[v]));
-		      
-		  snprintf(buf2, 100, "%s = %s",
-			   var_to_string(fctr->indep_var[0]),
-			   value_to_string(&(*fs)->id[0],fctr->indep_var[0]));
-		      
-		  strcat(buf1, buf2);
-		      
-		  if ( fctr->indep_var[1] ) 
-		    {
-		      sprintf(buf2, "; %s = %s)",
-			      var_to_string(fctr->indep_var[1]),
-			      value_to_string(&(*fs)->id[1],
-					      fctr->indep_var[1]));
-		      strcat(buf1, buf2);
-		    }
-		  else
-		    {
-		      strcat(buf1, ")");
-		    }
+		  const char *s = factor_to_string(fctr, *fs, dependent_vars[v]);
 
 		  if ( cmd.a_plot[XMN_PLT_NPPLOT] ) 
-		    np_plot(&(*fs)->m[v],buf1);
+		    np_plot(&(*fs)->m[v], s);
 
-		  
 		  if ( cmd.a_plot[XMN_PLT_HISTOGRAM] ) 
 		    {
 		      struct normal_curve normal;
@@ -311,7 +339,7 @@ output_examine(void)
 		      normal.stddev = (*fs)->m[v].stddev;
 		  
 		      histogram_plot((*fs)->m[v].histogram, 
-				     buf1,  &normal, 0);
+				     s,  &normal, 0);
 		    }
 		  
 		} /* for ( fs .... */
@@ -579,8 +607,9 @@ factor_calc(struct ccase *c, int case_no, double weight, int case_missing)
 
 	  if ( value_is_missing(val,var) || case_missing ) 
 	    val = 0;
-
-	  metrics_calc( &(*foo)->m[v], val, weight, case_no );
+	  
+	  metrics_calc( &(*foo)->m[v], val, weight, case_no);
+	  
 	}
 
       fctr = fctr->next;
@@ -652,7 +681,7 @@ run_examine(const struct casefile *cf, void *cmd_ )
 	  if ( value_is_missing(val,var) || case_missing ) 
 	    val = 0;
 
-	  metrics_calc(&totals[v], val, weight, case_no );
+	  metrics_calc(&totals[v], val, weight, case_no);
     
 	}
 
@@ -1037,7 +1066,6 @@ show_extremes(struct variable **dependent_var, int n_dep_var,
 
   tab_title (tbl, 0, _("Extreme Values"));
 
-
   tab_vline (tbl, TAL_2, n_cols - 2, 0, n_rows -1);
   tab_vline (tbl, TAL_1, n_cols - 1, 0, n_rows -1);
 
@@ -1054,9 +1082,6 @@ show_extremes(struct variable **dependent_var, int n_dep_var,
   tab_text (tbl, n_cols - 1, 0, TAB_CENTER | TAT_TITLE, _("Value"));
   tab_text (tbl, n_cols - 2, 0, TAB_CENTER | TAT_TITLE, _("Case Number"));
 
-
-
-
   for ( i = 0 ; i < n_dep_var ; ++i ) 
     {
 
@@ -1377,13 +1402,6 @@ show_descriptives(struct variable **dependent_var,
 
 
 
-
-
-
-
-
-
-
 /* Fill in the descriptives data */
 void
 populate_descriptives(struct tab_table *tbl, int col, int row, 
@@ -1602,6 +1620,133 @@ populate_descriptives(struct tab_table *tbl, int col, int row,
 }
 
 
+
+void
+box_plot_variables(const struct factor *fctr, 
+		   struct variable **vars, int n_vars, 
+		   const struct variable *id)
+{
+  int i;
+  struct factor_statistics **fs ;
+
+  if ( ! fctr ) 
+    {
+      box_plot_group(fctr, vars, n_vars, id);
+      return;
+    }
+
+  for ( fs = fctr->fs ; *fs ; ++fs ) 
+    {
+      double y_min = DBL_MAX;
+      double y_max = -DBL_MAX;
+      struct chart ch;
+
+      chart_initialise(&ch);
+
+      const char *s = factor_to_string(fctr, *fs, 0 );
+
+      chart_write_title(&ch, s);
+
+      for ( i = 0 ; i < n_vars ; ++i ) 
+	{
+	  y_max = max(y_max, (*fs)->m[i].max);
+	  y_min = min(y_min, (*fs)->m[i].min);
+	}
+      
+      boxplot_draw_yscale(&ch, y_max, y_min);
+	  
+      for ( i = 0 ; i < n_vars ; ++i ) 
+	{
+
+	  const double box_width = (ch.data_right - ch.data_left) 
+	    / (n_vars * 2.0 ) ;
+
+	  const double box_centre = ( i * 2 + 1) * box_width 
+	    + ch.data_left;
+	      
+	  boxplot_draw_boxplot(&ch,
+			       box_centre, box_width,
+			       &(*fs)->m[i],
+			       var_to_string(vars[i]));
+
+
+	}
+
+      chart_finalise(&ch);
+
+    }
+
+}
+
+
+
+/* Do a box plot, grouping all factors into one plot ;
+   each dependent variable has its own plot.
+*/
+void
+box_plot_group(const struct factor *fctr, 
+	       const struct variable **vars, 
+	       int n_vars,
+	       const struct variable *id)
+{
+  int i;
+
+  for ( i = 0 ; i < n_vars ; ++i ) 
+    {
+      struct factor_statistics **fs ;
+      struct chart ch;
+
+      chart_initialise(&ch);
+
+      boxplot_draw_yscale(&ch, totals[i].max, totals[i].min);
+
+      if ( fctr ) 
+	{
+	  int n_factors = 0;
+	  int f=0;
+	  for ( fs = fctr->fs ; *fs ; ++fs ) 
+	      ++n_factors;
+
+	  chart_write_title(&ch, _("Boxplot of %s vs. %s"), 
+			    var_to_string(vars[i]), var_to_string(fctr->indep_var[0]) );
+
+	  for ( fs = fctr->fs ; *fs ; ++fs ) 
+	    {
+	      
+	      const char *s = factor_to_string_concise(fctr, *fs);
+
+	      const double box_width = (ch.data_right - ch.data_left) 
+		/ (n_factors * 2.0 ) ;
+
+	      const double box_centre = ( f++ * 2 + 1) * box_width 
+		+ ch.data_left;
+	      
+	      boxplot_draw_boxplot(&ch,
+				   box_centre, box_width,
+				   &(*fs)->m[i],
+				   s);
+	    }
+	}
+      else
+	{
+	  const double box_width = (ch.data_right - ch.data_left) / 3.0;
+	  const double box_centre = (ch.data_right + ch.data_left) / 2.0;
+
+	  chart_write_title(&ch, _("Boxplot"));
+
+	  boxplot_draw_boxplot(&ch,
+			       box_centre,    box_width, 
+			       &totals[i],
+			       var_to_string(vars[i]) );
+	  
+	}
+
+      chart_finalise(&ch);
+    }
+
+}
+
+
 /* Plot the normal and detrended normal plots for m
    Label the plots with factorname */
 void
@@ -1920,17 +2065,17 @@ populate_percentiles(struct tab_table *tbl, int col, int row,
       if ( (*p)->p == 25 ) 
 	tab_float(tbl, col + i + 1 , row + 1, 
 		  TAB_CENTER,
-		  m->hinges[0], 8, 2);
+		  m->hinge[0], 8, 2);
 
       if ( (*p)->p == 50 ) 
 	tab_float(tbl, col + i + 1 , row + 1, 
 		  TAB_CENTER,
-		  m->hinges[1], 8, 2);
+		  m->hinge[1], 8, 2);
 
       if ( (*p)->p == 75 ) 
 	tab_float(tbl, col + i + 1 , row + 1, 
 		  TAB_CENTER,
-		  m->hinges[2], 8, 2);
+		  m->hinge[2], 8, 2);
 
 
       i++;
@@ -1938,8 +2083,69 @@ populate_percentiles(struct tab_table *tbl, int col, int row,
       p++;
     }
 
+}
+
 
 
+const char *
+factor_to_string(const struct factor *fctr, 
+		 struct factor_statistics *fs,
+		 const struct variable *var)
+{
+
+  static char buf1[100];
+  char buf2[100];
 
+  strcpy(buf1,"");
+
+  if (var)
+    sprintf(buf1, "%s (",var_to_string(var) );
+
+		      
+  snprintf(buf2, 100, "%s = %s",
+	   var_to_string(fctr->indep_var[0]),
+	   value_to_string(&fs->id[0],fctr->indep_var[0]));
+		      
+  strcat(buf1, buf2);
+		      
+  if ( fctr->indep_var[1] ) 
+    {
+      sprintf(buf2, "; %s = %s)",
+	      var_to_string(fctr->indep_var[1]),
+	      value_to_string(&fs->id[1],
+			      fctr->indep_var[1]));
+      strcat(buf1, buf2);
+    }
+  else
+    {
+      if ( var ) 
+	strcat(buf1, ")");
+    }
+
+  return buf1;
 }
 
+
+
+const char *
+factor_to_string_concise(const struct factor *fctr, 
+		 struct factor_statistics *fs)
+
+{
+
+  static char buf[100];
+
+  char buf2[100];
+
+  snprintf(buf, 100, "%s",
+	   value_to_string(&fs->id[0], fctr->indep_var[0]));
+		      
+  if ( fctr->indep_var[1] ) 
+    {
+      sprintf(buf2, ",%s)", value_to_string(&fs->id[1], fctr->indep_var[1]) );
+      strcat(buf, buf2);
+    }
+
+
+  return buf;
+}
diff --git a/src/factor_stats.c b/src/factor_stats.c
index 7e5ac8b4..7c4cce00 100644
--- a/src/factor_stats.c
+++ b/src/factor_stats.c
@@ -187,7 +187,7 @@ metrics_postcalc(struct metrics *m)
   /* Calculate the percentiles */
   ptiles(m->ptile_hash, m->wvp, m->n_data, m->n, m->ptile_alg);
 
-  tukey_hinges(m->wvp, m->n_data, m->n, m->hinges);
+  tukey_hinges(m->wvp, m->n_data, m->n, m->hinge);
 
   /* Special case here */
   if ( k1 + 1 == k2 ) 
diff --git a/src/factor_stats.h b/src/factor_stats.h
index f6394a8a..b05d7423 100644
--- a/src/factor_stats.h
+++ b/src/factor_stats.h
@@ -80,13 +80,11 @@ struct metrics
   enum pc_alg ptile_alg;
 
   /* Tukey's Hinges */
-  double hinges[3];
+  double hinge[3];
 
 };
 
 
-
-
 void metrics_precalc(struct metrics *m);
 
 void metrics_calc(struct metrics *m, const union value *f, double weight, 
diff --git a/src/percentiles.c b/src/percentiles.c
index 9719676d..1c8eef2a 100644
--- a/src/percentiles.c
+++ b/src/percentiles.c
@@ -80,18 +80,22 @@ ptile_round(const struct weighted_value **wv,
 	    const struct ptile_params *par)
 {
   double x;
+  double a=0;
+
+  if ( par->k1 >= 0 ) 
+    a = wv[par->k1]->v.f;
 
   if ( wv[par->k1 + 1]->w >= 1 )
     {
       if ( par->g1_star < 0.5 ) 
-	x = wv[par->k1]->v.f;
+	x = a;
       else
 	x = wv[par->k1 + 1]->v.f;
     }
   else
     {
       if ( par->g1 < 0.5 ) 
-	x = wv[par->k1]->v.f;
+	x = a;
       else
 	x = wv[par->k1 + 1]->v.f;
 
@@ -105,6 +109,9 @@ double
 ptile_haverage(const struct weighted_value **wv, 
 	       const struct ptile_params *par)
 {
+
+  double a=0;
+
   if ( par->g2_star >= 1.0 ) 
       return wv[par->k2 + 1]->v.f ;
 
@@ -117,15 +124,17 @@ ptile_haverage(const struct weighted_value **wv,
       return wv[par->k2]->v.f;
     }
 
-  assert(par->k2 >= 0);
+  /* Ditto for k2 < 0 */
+  if ( par->k2 >= 0 ) 
+    {
+      a = wv[par->k2]->v.f;
+    }
 
   if ( wv[par->k2 + 1]->w >= 1.0 ) 
-    return ( (1 - par->g2_star) *  wv[par->k2]->v.f
-	     + 
+    return ( (1 - par->g2_star) *  a   + 
 	     par->g2_star * wv[par->k2 + 1]->v.f);
   else
-    return ( (1 - par->g2) *  wv[par->k2]->v.f
-	     + 
+    return ( (1 - par->g2) * a + 
 	     par->g2 * wv[par->k2 + 1]->v.f);
 
 }
@@ -137,16 +146,21 @@ double
 ptile_waverage(const struct weighted_value **wv, 
 	       const struct ptile_params *par)
 {
+  double a=0;
+
   if ( par->g1_star >= 1.0 ) 
       return wv[par->k1 + 1]->v.f ;
 
+  if ( par->k1 >= 0 ) 
+    {
+      a = wv[par->k1]->v.f;
+    }
+
   if ( wv[par->k1 + 1]->w >= 1.0 ) 
-    return ( (1 - par->g1_star) *  wv[par->k1]->v.f
-	     + 
+    return ( (1 - par->g1_star) * a + 
 	     par->g1_star * wv[par->k1 + 1]->v.f);
   else
-    return ( (1 - par->g1) *  wv[par->k1]->v.f
-	     + 
+    return ( (1 - par->g1) * a + 
 	     par->g1 * wv[par->k1 + 1]->v.f);
 }
 
@@ -305,7 +319,8 @@ void
 tukey_hinges(const struct weighted_value **wv,
 	     int n_data, 
 	     double w,
-	     double hinges[3])
+	     double hinge[3]
+	     )
 {
   int i;
   double c_star = DBL_MAX;
@@ -351,27 +366,28 @@ tukey_hinges(const struct weighted_value **wv,
 
       if ( a_star >= 1.0 ) 
 	{
-	  hinges[i] = wv[h[i] + 1]->v.f ;
+	  hinge[i] = wv[h[i] + 1]->v.f ;
 	  continue;
 	}
 
       if ( wv[h[i]+1]->w >= 1)
 	{
-	  hinges[i] = ( 1 - a_star)* wv[h[i]]->v.f
+	  hinge[i] = ( 1 - a_star)* wv[h[i]]->v.f
 	    + a_star * wv[h[i]+1]->v.f;
 
 	  continue;
 	}
 
-      hinges[i] = ( 1 - a)* wv[h[i]]->v.f + a * wv[h[i]+1]->v.f;
+      hinge[i] = ( 1 - a)* wv[h[i]]->v.f + a * wv[h[i]+1]->v.f;
       
     }
 
-  assert(hinges[0] <= hinges[1]);
-  assert(hinges[1] <= hinges[2]);
+  assert(hinge[0] <= hinge[1]);
+  assert(hinge[1] <= hinge[2]);
 
 }
 
+
 int
 ptile_compare(const struct percentile *p1, 
 		   const struct percentile *p2, 
diff --git a/src/percentiles.h b/src/percentiles.h
index 8baba9fa..e330aabd 100644
--- a/src/percentiles.h
+++ b/src/percentiles.h
@@ -64,7 +64,7 @@ void ptiles(struct hsh_table *pc_hash,
 	    enum pc_alg algorithm);
 
 
-/* Calculate Tukey's Hinges */
+/* Calculate Tukey's Hinges and the Whiskers for the box plot*/
 void tukey_hinges(const struct weighted_value **wv,
 		  int n_data, 
 		  double w,
diff --git a/src/piechart.c b/src/piechart.c
index 14115e4c..53c2b5fd 100644
--- a/src/piechart.c
+++ b/src/piechart.c
@@ -27,6 +27,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 #include <stdio.h>
 #include "str.h"
 #include "value-labels.h"
+#include "misc.h"
 
 
 /* Pie charts of course need to know Pi :) */
@@ -35,8 +36,6 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 #endif
 
 
-#define min(A,B) ((A>B)?B:A)
-
 
 /* Draw a single slice of the pie */
 static void
diff --git a/src/q2c.c b/src/q2c.c
index 5d188bbc..aaf3343c 100644
--- a/src/q2c.c
+++ b/src/q2c.c
@@ -1611,7 +1611,7 @@ dump_subcommand (const subcommand *sbc)
     {
       dump (0, "p->%sv_%s = parse_variable ();",
 	    st_lower (sbc->prefix), st_lower (sbc->name));
-      dump (1, "if (p->%sv_%s)",
+      dump (1, "if (!p->%sv_%s)",
 	    st_lower (sbc->prefix), st_lower (sbc->name));
       dump (0, "goto lossage;");
       outdent ();
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 3b4de758..a48b9092 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -11,6 +11,7 @@ TESTS = \
 	command/erase.sh \
 	command/examine.sh \
 	command/examine-extremes.sh \
+	command/examine-percentiles.sh \
 	command/file-label.sh \
 	command/filter.sh \
 	command/flip.sh \
diff --git a/tests/command/examine-percentiles.sh b/tests/command/examine-percentiles.sh
new file mode 100755
index 00000000..b7982d30
--- /dev/null
+++ b/tests/command/examine-percentiles.sh
@@ -0,0 +1,198 @@
+#!/bin/sh
+
+# This program tests  the PERCENTILES subcommand of the EXAMINE command.
+# In particular it tests that it behaves properly when there are only 
+# a few cases
+
+TEMPDIR=/tmp/pspp-tst-$$
+
+here=`pwd`;
+
+# ensure that top_srcdir is absolute
+cd $top_srcdir; top_srcdir=`pwd`
+
+export STAT_CONFIG_PATH=$top_srcdir/config
+
+
+cleanup()
+{
+     rm -rf $TEMPDIR
+}
+
+
+fail()
+{
+    echo $activity
+    echo FAILED
+    cleanup;
+    exit 1;
+}
+
+
+no_result()
+{
+    echo $activity
+    echo NO RESULT;
+    cleanup;
+    exit 2;
+}
+
+pass()
+{
+    cleanup;
+    exit 0;
+}
+
+mkdir -p $TEMPDIR
+
+cd $TEMPDIR
+
+activity="create program"
+cat > $TEMPDIR/out.stat <<EOF
+DATA LIST LIST /x *.
+BEGIN DATA.
+2.00 
+8.00 
+5.00 
+END DATA.
+
+EXAMINE /x
+	/PERCENTILES=HAVERAGE.
+
+EXAMINE /x
+	/PERCENTILES=WAVERAGE.
+
+EXAMINE /x
+	/PERCENTILES=ROUND.
+
+EXAMINE /x
+	/PERCENTILES=EMPIRICAL.
+
+EXAMINE /x
+	/PERCENTILES=AEMPIRICAL.
+EOF
+if [ $? -ne 0 ] ; then no_result ; fi
+
+activity="run program"
+$SUPERVISOR $here/../src/pspp -o raw-ascii $TEMPDIR/out.stat
+if [ $? -ne 0 ] ; then no_result ; fi
+
+
+activity="compare results"
+diff $TEMPDIR/pspp.list - << EOF
+1.1 DATA LIST.  Reading free-form data from the command file.
++--------+------+
+|Variable|Format|
+#========#======#
+|X       |F8.0  |
++--------+------+
+
+2.1 EXAMINE.  Case Processing Summary
+#=#=============================#
+# #            Cases            #
+# #---------+---------+---------#
+# #  Valid  | Missing |  Total  #
+# #-+-------+-+-------+-+-------#
+# #N|Percent|N|Percent|N|Percent#
+#=#=#=======#=#=======#=#=======#
+#X#3|   100%|0|     0%|3|   100%#
+#=#=#=======#=#=======#=#=======#
+
+2.2 EXAMINE.  Percentiles
+#================#================================#
+#                #             Percentiles        #
+#                #---+---+----+----+----+----+----#
+#                # 5 | 10| 25 | 50 | 75 | 90 | 95 #
+#=#==============#===#===#====#====#====#====#====#
+#X|HAverage      #.40|.80|2.00|5.00|8.00|8.00|8.00#
+# |Tukey's Hinges#   |   |3.50|5.00|6.50|    |    #
+#=#==============#===#===#====#====#====#====#====#
+
+3.1 EXAMINE.  Case Processing Summary
+#=#=============================#
+# #            Cases            #
+# #---------+---------+---------#
+# #  Valid  | Missing |  Total  #
+# #-+-------+-+-------+-+-------#
+# #N|Percent|N|Percent|N|Percent#
+#=#=#=======#=#=======#=#=======#
+#X#3|   100%|0|     0%|3|   100%#
+#=#=#=======#=#=======#=#=======#
+
+3.2 EXAMINE.  Percentiles
+#==================#================================#
+#                  #             Percentiles        #
+#                  #---+---+----+----+----+----+----#
+#                  # 5 | 10| 25 | 50 | 75 | 90 | 95 #
+#=#================#===#===#====#====#====#====#====#
+#X|Weighted Average#.30|.60|1.50|3.50|5.75|7.10|7.55#
+# |Tukey's Hinges  #   |   |3.50|5.00|6.50|    |    #
+#=#================#===#===#====#====#====#====#====#
+
+4.1 EXAMINE.  Case Processing Summary
+#=#=============================#
+# #            Cases            #
+# #---------+---------+---------#
+# #  Valid  | Missing |  Total  #
+# #-+-------+-+-------+-+-------#
+# #N|Percent|N|Percent|N|Percent#
+#=#=#=======#=#=======#=#=======#
+#X#3|   100%|0|     0%|3|   100%#
+#=#=#=======#=#=======#=#=======#
+
+4.2 EXAMINE.  Percentiles
+#================#================================#
+#                #             Percentiles        #
+#                #---+---+----+----+----+----+----#
+#                # 5 | 10| 25 | 50 | 75 | 90 | 95 #
+#=#==============#===#===#====#====#====#====#====#
+#X|Rounded       #.00|.00|2.00|5.00|5.00|8.00|8.00#
+# |Tukey's Hinges#   |   |3.50|5.00|6.50|    |    #
+#=#==============#===#===#====#====#====#====#====#
+
+5.1 EXAMINE.  Case Processing Summary
+#=#=============================#
+# #            Cases            #
+# #---------+---------+---------#
+# #  Valid  | Missing |  Total  #
+# #-+-------+-+-------+-+-------#
+# #N|Percent|N|Percent|N|Percent#
+#=#=#=======#=#=======#=#=======#
+#X#3|   100%|0|     0%|3|   100%#
+#=#=#=======#=#=======#=#=======#
+
+5.2 EXAMINE.  Percentiles
+#================#==================================#
+#                #              Percentiles         #
+#                #----+----+----+----+----+----+----#
+#                #  5 | 10 | 25 | 50 | 75 | 90 | 95 #
+#=#==============#====#====#====#====#====#====#====#
+#X|Empirical     #2.00|2.00|2.00|5.00|8.00|8.00|8.00#
+# |Tukey's Hinges#    |    |3.50|5.00|6.50|    |    #
+#=#==============#====#====#====#====#====#====#====#
+
+6.1 EXAMINE.  Case Processing Summary
+#=#=============================#
+# #            Cases            #
+# #---------+---------+---------#
+# #  Valid  | Missing |  Total  #
+# #-+-------+-+-------+-+-------#
+# #N|Percent|N|Percent|N|Percent#
+#=#=#=======#=#=======#=#=======#
+#X#3|   100%|0|     0%|3|   100%#
+#=#=#=======#=#=======#=#=======#
+
+6.2 EXAMINE.  Percentiles
+#==========================#==================================#
+#                          #              Percentiles         #
+#                          #----+----+----+----+----+----+----#
+#                          #  5 | 10 | 25 | 50 | 75 | 90 | 95 #
+#=#========================#====#====#====#====#====#====#====#
+#X|Empirical with averaging#2.00|2.00|2.00|5.00|8.00|8.00|8.00#
+# |Tukey's Hinges          #    |    |3.50|5.00|6.50|    |    #
+#=#========================#====#====#====#====#====#====#====#
+
+EOF
+if [ $? -ne 0 ] ; then fail ; fi
+
+pass