-@node Statistics, Utilities, Conditionals and Looping, Top
+@node Statistics
@chapter Statistics
This chapter documents the statistical procedures that PSPP supports so
* FREQUENCIES:: Frequency tables.
* EXAMINE:: Testing data for normality.
* CROSSTABS:: Crosstabulation tables.
+* NPAR TESTS:: Nonparametric tests.
* T-TEST:: Test hypotheses about means.
* ONEWAY:: One way analysis of variance.
* RANK:: Compute rank scores.
* REGRESSION:: Linear regression.
@end menu
-@node DESCRIPTIVES, FREQUENCIES, Statistics, Statistics
+@node DESCRIPTIVES
@section DESCRIPTIVES
@vindex DESCRIPTIVES
and D settings request an ascending or descending sort order,
respectively.
-@node FREQUENCIES, EXAMINE, DESCRIPTIVES, Statistics
+@node FREQUENCIES
@section FREQUENCIES
@vindex FREQUENCIES
displayed slices to a given range of values. The MISSING keyword adds
slices for missing values.
-@node EXAMINE, CROSSTABS, FREQUENCIES, Statistics
+@node EXAMINE
@comment node-name, next, previous, up
@section EXAMINE
@vindex EXAMINE
large quantity of output.
-@node CROSSTABS, T-TEST, EXAMINE, Statistics
+@node CROSSTABS
@section CROSSTABS
@vindex CROSSTABS
Fixes for any of these deficiencies would be welcomed.
-@node T-TEST, ONEWAY, CROSSTABS, Statistics
+@node NPAR TESTS
+@section NPAR TESTS
+
+@vindex NPAR TESTS
+@cindex nonparametric tests
+
+@display
+NPAR TESTS
+
+ nonparametric test subcommands
+ .
+ .
+ .
+
+ [ /STATISTICS=@{DESCRIPTIVES@} ]
+
+ [ /MISSING=@{ANALYSIS, LISTWISE@} @{INCLUDE, EXCLUDE@} ]
+@end display
+
+NPAR TESTS performs nonparametric tests.
+Non parametric tests make very few assumptions about the distribution of the
+data.
+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.
+
+
+@menu
+* BINOMIAL:: Binomial Test
+* CHISQUARE:: Chisquare Test
+@end menu
+
+
+@node BINOMIAL
+@subsection Binomial test
+@vindex BINOMIAL
+@cindex binomial test
+
+@display
+ [ /BINOMIAL[(p)]=var_list[(value1[, value2)] ] ]
+@end display
+
+The binomial test 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.
+The default value of 0.5 is assumed if @var{p} is omitted.
+
+If a single value appears after the variable list, then that value is
+used as the threshold to partition the observed values. Values less
+than or equal to the threshold value form the first category. Values
+greater than the threshold form the second category.
+
+If two values appear after the variable list, then they will be used
+as the values which a variable must take to be in the respective
+category.
+Cases for which a variable takes a value equal to neither of the specified
+values, take no part in the test for that variable.
+
+If no values appear, then the variable must assume dichotomous
+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
+reported. For any other test proportion, a one tailed test is
+reported.
+For one tailed tests, if the test proportion is less than
+or equal to the observed proportion, then the significance of
+observing the observed proportion or more is reported.
+If the test proportion is more than the observed proportion, then the
+significance of observing the observed proportion or less is reported.
+That is to say, the test is always performed in the observed
+direction.
+
+PSPP uses a very precise approximation to the gamma function to
+compute the binomial significance. Thus, exact results are reported
+even for very large sample sizes.
+
+
+
+@node CHISQUARE
+@subsection Chisquare test
+@vindex CHISQUARE
+@cindex chisquare test
+
+
+@display
+ [ /CHISQUARE=var_list[(lo,hi)] [/EXPECTED=@{EQUAL|f1, f2 @dots{} fn@}] ]
+@end display
+
+
+The chisquare test 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
+outside the specified range are excluded from the analysis.
+
+The /EXPECTED subcommand specifies the expected values of each
+category.
+There must be exactly one non-zero expected value, for each observed
+category, or the EQUAL keywork must be specified.
+You may use the notation @var{n}*@var{f} to specify @var{n}
+consecutive expected categories all taking a frequency of @var{f}.
+The frequencies given are proportions, not absolute frequencies. The
+sum of the frequencies need not be 1.
+If no /EXPECTED subcommand is given, then then equal frequencies
+are expected.
+
+
+@node T-TEST
@comment node-name, next, previous, up
@section T-TEST
@vindex T-TEST
+
@display
T-TEST
/MISSING=@{ANALYSIS,LISTWISE@} @{EXCLUDE,INCLUDE@}
* Paired Samples Mode:: Testing two interdependent groups for equal mean
@end menu
-@node One Sample Mode, Independent Samples Mode, T-TEST, T-TEST
+@node One Sample Mode
@subsection One Sample Mode
The @cmd{TESTVAL} subcommand invokes the One Sample mode.
In this mode, you must also use the @cmd{/VARIABLES} subcommand to
tell PSPP which variables you wish to test.
-@node Independent Samples Mode, Paired Samples Mode, One Sample Mode, T-TEST
+@node Independent Samples Mode
@comment node-name, next, previous, up
@subsection Independent Samples Mode
If the independent variable is numeric,
it is acceptable to specify only one value inside the parentheses.
If you do this, cases where the independent variable is
-less than or equal to this value belong to the first group, and cases
-greater than this value belong to the second group.
+greater than or equal to this value belong to the first group, and cases
+less than this value belong to the second group.
When using this form of the @cmd{GROUPS} subcommand, missing values in
the independent variable are excluded on a listwise basis, regardless
of whether @cmd{/MISSING=LISTWISE} was specified.
-@node Paired Samples Mode, , Independent Samples Mode, T-TEST
+@node Paired Samples Mode
@comment node-name, next, previous, up
@subsection Paired Samples Mode
The @cmd{PAIRS} subcommand introduces Paired Samples mode.
Use this mode when repeated measures have been taken from the same
samples.
-If the the @code{WITH} keyword is omitted, then tables for all
+If the @code{WITH} keyword is omitted, then tables for all
combinations of variables given in the @cmd{PAIRS} subcommand are
generated.
If the @code{WITH} keyword is given, and the @code{(PAIRED)} keyword
@code{WITH} are generated.
-@node ONEWAY, RANK, T-TEST, Statistics
+@node ONEWAY
@comment node-name, next, previous, up
@section ONEWAY
to specify different contrast tests.
@setfilename ignored
-@node RANK, REGRESSION, ONEWAY, Statistics
+@node RANK
@comment node-name, next, previous, up
@section RANK
projects / pspp-builds.git / blobdiff