X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=doc%2Fstatistics.texi;h=985560604b02b52b02440dcd39a36bd1b773c118;hb=9a331fe64eb814ae5c1322e21717a04fb254bf65;hp=8fa93b1566a38fe304836d8d473fcc2dde7189b3;hpb=92f9121c49de9f91d9d743b5dc854cf701713dc5;p=pspp-builds.git diff --git a/doc/statistics.texi b/doc/statistics.texi index 8fa93b15..98556060 100644 --- a/doc/statistics.texi +++ b/doc/statistics.texi @@ -14,6 +14,7 @@ far. * ONEWAY:: One way analysis of variance. * RANK:: Compute rank scores. * REGRESSION:: Linear regression. +* RELIABILITY:: Reliability analysis. @end menu @node DESCRIPTIVES @@ -232,7 +233,7 @@ EXAMINE /PLOT=@{BOXPLOT, NPPLOT, HISTOGRAM, ALL, NONE@} /CINTERVAL n /COMPARE=@{GROUPS,VARIABLES@} - /ID=@{case_number, var_name@} + /ID=var_name /@{TOTAL,NOTOTAL@} /PERCENTILE=[value_list]=@{HAVERAGE, WAVERAGE, ROUND, AEMPIRICAL, EMPIRICAL @} /MISSING=@{LISTWISE, PAIRWISE@} [@{EXCLUDE, INCLUDE@}] @@ -271,6 +272,12 @@ 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 ID subcommand also pertains to boxplots. If given, it must +specify a variable name. Outliers and extreme cases plotted in +boxplots will be labelled with the case from that variable. Numeric or +string variables are permissible. If the ID subcommand is not given, +then the casenumber will be used for labelling. The CINTERVAL subcommand specifies the confidence interval to use in calculation of the descriptives command. The default it 95%. @@ -499,6 +506,8 @@ NPAR TESTS [ /STATISTICS=@{DESCRIPTIVES@} ] [ /MISSING=@{ANALYSIS, LISTWISE@} @{INCLUDE, EXCLUDE@} ] + + [ /METHOD=EXACT [ TIMER [(n)] ] ] @end display NPAR TESTS performs nonparametric tests. @@ -508,10 +517,21 @@ 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 @end menu @@ -591,6 +611,34 @@ sum of the frequencies need not be 1. If no /EXPECTED subcommand is given, then then equal frequencies are expected. +@node WILCOXON +@subsection Wilcoxon +@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 means of the +variables listed. The test does not make any assumptions about the +variances of the samples. + +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. + +If the number of observations is large, and exact tests have been +requested. then the test may take a very long time to complete. @node T-TEST @comment node-name, next, previous, up @@ -766,7 +814,6 @@ 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 @@ -831,3 +878,50 @@ user-missing are to be excluded from the rank scores. A setting of INCLUDE means they are to be included. The default is EXCLUDE. @include regression.texi + + +@node RELIABILITY +@section RELIABILITY + +@vindex RELIABILITY +@display +RELIABILITY + /VARIABLES=var_list + /SCALE (@var{name}) = @{var_list, ALL@} + /MODEL=@{ALPHA, SPLIT[(N)]@} + /SUMMARY=@{TOTAL,ALL@} + /MISSING=@{EXCLUDE,INCLUDE@} +@end display + +@cindex Cronbach's Alpha +The @cmd{RELIABILTY} command performs reliablity analysis on the data. + +The VARIABLES subcommand is required. It determines the set of variables +upon which analysis is to be performed. + +The SCALE subcommand determines which variables reliability is to be +calculated for. If it is omitted, then analysis for all variables named +in the VARIABLES subcommand will be used. +Optionally, the @var{name} parameter may be specified to set a string name +for the scale. + +The MODEL subcommand determines the type of analysis. If ALPHA is specified, +then Cronbach's Alpha is calculated for the scale. If the model is SPLIT, +then the variables are divided into 2 subsets. An optional parameter +@var{N} may be given, to specify how many variables to be in the first subset. +If @var{N} is omitted, then it defaults to one half of the variables in the +scale, or one half minus one if there are an odd number of variables. +The default model is ALPHA. + +By default, any cases with user missing, or system missing values for +any variables given +in the VARIABLES subcommand will be omitted from analysis. +The MISSING subcommand determines whether user missing values are to +be included or excluded in the analysis. + +The SUMMARY subcommand determines the type of summary analysis to be performed. +Currently there is only one type: SUMMARY=TOTAL, which displays per-item +analysis tested against the totals. + + +