X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=doc%2Fstatistics.texi;h=5430c6bc6958e7e22b2a6b9cff98cd65ccd48b22;hb=a091aa55567a4f2a9ecc08f126a959497be43f22;hp=a67402c0e13bd178dc720078f5cf819ee829e160;hpb=2287a5970f043d5e18ebaf0013d0a2968c6f6051;p=pspp-builds.git diff --git a/doc/statistics.texi b/doc/statistics.texi index a67402c0..5430c6bc 100644 --- a/doc/statistics.texi +++ b/doc/statistics.texi @@ -205,12 +205,13 @@ boundaries of the data set divided into the specified number of ranges. For instance, @code{/NTILES=4} would cause quartiles to be reported. The HISTOGRAM subcommand causes the output to include a histogram for -each specified variable. The X axis by default ranges from the +each specified numeric variable. The X axis by default ranges from the minimum to the maximum value observed in the data, but the MINIMUM and MAXIMUM keywords can set an explicit range. The Y axis by default is labeled in frequencies; use the PERCENT keyword to causes it to be labeled in percent of the total observed count. Specify NORMAL to superimpose a normal curve on the histogram. +Histograms are not created for string variables. The PIECHART adds a pie chart for each variable to the data. Each slice represents one value, with the size of the slice proportional to @@ -506,6 +507,8 @@ NPAR TESTS [ /STATISTICS=@{DESCRIPTIVES@} ] [ /MISSING=@{ANALYSIS, LISTWISE@} @{INCLUDE, EXCLUDE@} ] + + [ /METHOD=EXACT [ TIMER [(n)] ] ] @end display NPAR TESTS performs nonparametric tests. @@ -515,10 +518,22 @@ One or more tests may be specified by using the corresponding subcommand. If the /STATISTICS subcommand is also specified, then summary statistics are produces for each variable that is the subject of any test. +Certain tests may take a long time to execute, if an exact figure is required. +Therefore, by default asymptotic approximations are used unless the +subcommand /METHOD=EXACT is specified. +Exact tests give more accurate results, but may take an unacceptably long +time to perform. If the TIMER keyword is used, it sets a maximum time, +after which the test will be abandoned, and a warning message printed. +The time, in minutes, should be specified in parentheses after the TIMER keyword. +If the TIMER keyword is given without this figure, then a default value of 5 minutes +is used. + @menu * BINOMIAL:: Binomial Test * CHISQUARE:: Chisquare Test +* WILCOXON:: Wilcoxon Signed Ranks Test +* SIGN:: The Sign Test @end menu @@ -531,7 +546,7 @@ produces for each variable that is the subject of any test. [ /BINOMIAL[(p)]=var_list[(value1[, value2)] ] ] @end display -The binomial test compares the observed distribution of a dichotomous +The /BINOMIAL subcommand compares the observed distribution of a dichotomous variable with that of a binomial distribution. The variable @var{p} specifies the test proportion of the binomial distribution. @@ -553,7 +568,7 @@ values. If more than two distinct, non-missing values for a variable under test are encountered then an error occurs. -If the test proportion is equal to 0.5, then a one tailed test is +If the test proportion is equal to 0.5, then a two tailed test is reported. For any other test proportion, a one tailed test is reported. For one tailed tests, if the test proportion is less than @@ -571,7 +586,7 @@ even for very large sample sizes. @node CHISQUARE -@subsection Chisquare test +@subsection Chisquare Test @vindex CHISQUARE @cindex chisquare test @@ -581,7 +596,7 @@ even for very large sample sizes. @end display -The chisquare test produces a chi-square statistic for the differences +The /CHISQUARE subcommand produces a chi-square statistic for the differences between the expected and observed frequencies of the categories of a variable. Optionally, a range of values may appear after the variable list. If a range is given, then non integer values are truncated, and values @@ -598,6 +613,59 @@ sum of the frequencies need not be 1. If no /EXPECTED subcommand is given, then then equal frequencies are expected. +@node WILCOXON +@subsection Wilcoxon Matched Pairs Signed Ranks Test +@comment node-name, next, previous, up +@vindex WILCOXON +@cindex wilcoxon matched pairs signed ranks test + +@display + [ /WILCOXON varlist [ WITH varlist [ (PAIRED) ]]] +@end display + +The /WILCOXON subcommand tests for differences between medians of the +variables listed. +The test does not make any assumptions about the variances of the samples. +It does however assume that the distribution is symetrical. + +If the @code{WITH} keyword is omitted, then tests for all +combinations of the listed variables are performed. +If the @code{WITH} keyword is given, and the @code{(PAIRED)} keyword +is also given, then the number of variables preceding @code{WITH} +must be the same as the number following it. +In this case, tests for each respective pair of variables are +performed. +If the @code{WITH} keyword is given, but the +@code{(PAIRED)} keyword is omitted, then tests for each combination +of variable preceding @code{WITH} against variable following +@code{WITH} are performed. + + +@node SIGN +@subsection Sign Test +@vindex SIGN +@cindex sign test + +@display + [ /SIGN varlist [ WITH varlist [ (PAIRED) ]]] +@end display + +The /SIGN subcommand tests for differences between medians of the +variables listed. +The test does not make any assumptions about the +distribution of the data. + +If the @code{WITH} keyword is omitted, then tests for all +combinations of the listed variables are performed. +If the @code{WITH} keyword is given, and the @code{(PAIRED)} keyword +is also given, then the number of variables preceding @code{WITH} +must be the same as the number following it. +In this case, tests for each respective pair of variables are +performed. +If the @code{WITH} keyword is given, but the +@code{(PAIRED)} keyword is omitted, then tests for each combination +of variable preceding @code{WITH} against variable following +@code{WITH} are performed. @node T-TEST @comment node-name, next, previous, up @@ -773,7 +841,6 @@ If the total sum of the coefficients are not zero, then PSPP will display a warning, but will proceed with the analysis. The @code{CONTRAST} subcommand may be given up to 10 times in order to specify different contrast tests. -@setfilename ignored @node RANK @comment node-name, next, previous, up