Visualizing Categorical Data: goodfit

The goodfit macro ( get goodfit.sas)

Goodness of fit tests for discrete distributions

The data may consist either of individual observations on a single variable, or a grouped frequency distribution.

The parameter(s) of the distribution may be specified as constants or may be estimated from the data.

Usage

  %goodfit(var=k, freq=freq, dist=binomial);

You must specify a VAR= analysis variable and the keyword for the distribution to be fit with the DIST= parameter. All other parameters are optional.

Parameters

DATA=

Specifies the name of the input data set to be analyzed. [Default: DATA=_LAST_]

VAR=

Specifies the name of the variable to be analyzed, the basic count variable.

FREQ=

Specifies the name of a frequency variable for a grouped data set. If no FREQ= variable is specified, the program assumes the data set is ungrouped, and calculates frequencies using PROC FREQ. In this case you can specify a SAS format with the FORMAT= parameter to control the way the observations are grouped.

DIST=

Specifies the name of the discrete distribution to be fit. The allowable values are: UNIFORM, DISCRETE, BINOMIAL, POISSON, NEGBIN, GEOMETRIC, LOGSERIES.

PARM=

Specifies the value of parameter(s) for the distribution being fit. If PARM= is not specified, the parameter(s) are estimated using maximum likelihood or method of moment estimators.

SUMAT=

For a distribution where frequencies for values of the VAR= variable = k have been lumped into a single category, specify SUMAT=k causes the macro to sum the probabilities and fitted frequencies for all values >= k. [Default: SUMAT=10000]

FORMAT=

The name of a SAS format used when no FREQ= variable has been specified.

OUT=

Name of the output data set containing the grouped frequency distribution, estimated fitted frequencies (EXP) and the values of the Pearson (CHI) and deviance (DEV) residuals. [Default: OUT=FIT]

OUTSTAT=

Name of the output data set containing goodness-of-fit statistics. [Default: OUTSTAT=STATS]

Example

%include vcd(goodfit);        *-- or include in an autocall library;

%goodfit();

See also