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DISTANCE Procedure


DISTANCE Procedure

9.1  

The new DISTANCE procedure computes various measures of distance, dissimilarity, or similarity between the observations (rows) of a SAS data set. These proximity measures are stored as a lower triangular matrix or a square matrix in an output data set (depending on the SHAPE= option) that can then be used as input to the CLUSTER, MDS, and MODECLUS procedures. The input data set may contain numeric or character variables, or both, depending on which proximity measure is used. PROC DISTANCE also provides various nonparametric and parametric methods for standardizing variables . Distance matrices are used frequently in data mining, genomics, marketing, financial analysis, management science, education, chemistry , psychology, biology, and various other fields.



FACTOR Procedure

The NOPROMAXNORM option turns off the default row normalization of the prerotated factor pattern, which is used in computing the promax target matrix.

You can now produce standard errors and confidence limits with the METHOD=ML option for the PROMAX factor solutions. You can obtain the standard errors with the SE option, control the coverage displays with the COVER= option, and set the coverage level with the ALPHA= option.



FREQ Procedure

The BDT option includes Tarone s adjustment in the Breslow-Day test for homogeneity of odds ratios. Refer to Agresti (1996) and Tarone (1985).

The ZEROS option in the WEIGHT statement includes zero-weight observations in the analysis. (By default, PROC FREQ does not process zero-weight observations.) With the ZEROS option, PROC FREQ displays zero-weight levels in crosstabulation and frequency tables. For one-way tables, the ZEROS option includes zero-weight levels in chi-square tests and binomial statistics. For multiway tables, the ZEROS option includes zero-weight levels in kappa statistics.

The CROSSLIST option displays crosstabulation tables in ODS column format. Unlike the default crosstabulation table, the CROSSLIST table has a table definition that you can customize with PROC TEMPLATE. The NLEVELS option provides a table with the number of levels for all TABLES statement variables .

9.1  

The FREQ procedure now produces exact confidence limits for the common odds ratio and related tests.



GENMOD Procedure

The GENMOD procedure now forms classification groups using the full formatted length of the CLASS variable levels. Several new full-rank CLASS variable parameterizations are now available: polynomial, orthogonal polynomial, effect, orthogonal effect, reference, orthogonal reference, ordinal, and orthogonal ordinal. The default parameterization remains the same less-than -full-rank parameterization used in previous releases.

Zero is now a valid value for the negative binomial dispersion parameter corresponding to the Poisson distribution. If a fixed value of zero is specified, a score test for overdispersion (Cameron and Trivedi 1998) is computed.

9.1  

As an experimental feature, PROC GENMOD now provides model assessment based on aggregates of residuals.



GLM Procedure

The GLM procedure now forms classification groups using the full formatted length of the CLASS variable levels.

In addition, you can compute exact p -values for three of the four multivariate tests (Wilks Lambda, the Hotelling-Lawley Trace, and Roy s Greatest Root) andanimproved F - approximation for the fourth (Pillai s Trace). The default MSTAT=FAPPROX in the MANOVA and REPEATED statements produces multivariate tests using approximations based on the F distribution. Specifying MSTAT=EXACT computes exact p -values for three of the four tests (Wilks Lambda, the Hotelling-Lawley Trace, and Roy s Greatest Root) and an improved F -approximation for the fourth (Pillai s Trace).