## Input Data Set of Statistics

PROC TTEST accepts data containing either observation
values or summary statistics.
It assumes that the DATA= data set contains
statistics if it contains a character variable
with name _TYPE_ or _STAT_. The TTEST procedure
expects this character variable to contain the
names of statistics. If both _TYPE_ and _STAT_
variables exist and are of type character, PROC
TTEST expects _TYPE_ to contain the names of
statistics including `N', `MEAN', and `STD' for each
BY group (or for each class within each BY group for two-sample
*t* tests). If no `N', `MEAN', or `STD' statistics exist,
an error message is printed.
FREQ, WEIGHT, and PAIRED statements cannot be used with
input data sets of statistics. BY, CLASS, and VAR
statements are the same regardless of data set type.
For paired comparisons, see the _DIF_ values for
the _TYPE_=T observations in output produced by the
OUTSTATS= option in the PROC COMPARE
statement (refer to the *SAS Procedures Guide*).

Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.