If you specify the keyword T, PROC SURVEYMEANS computes the t-value for testing that the population mean equals zero, 
. The test statistic equals
The two-sided p-value for this test is
where T is a random variable with the t distribution with df degrees of freedom.
![\[ t(\widehat{{\bar{Y}}}) = {\widehat{{\bar{Y}}}} ~ / ~ {\mbox{StdErr}(\widehat{{\bar{Y}}})} \]](images/statug_surveymeans0050.png){kind=small}
![\[ \mbox{Prob}(~ |T|>|t(\widehat{{\bar{Y}}})|~ ) \]](images/statug_surveymeans0051.png){kind=small}