PROC TTEST Statement

Chapter Contents

The TTEST Procedure

PROC TTEST Statement

PROC TTEST < options > ;

The following options can appear in the PROC TTEST statement.

ALPHA=p: specifies that confidence intervals are to be 100(1-p)% confidence intervals, where 0<p<1. By default, PROC TTEST uses ALPHA=0.05. If p is 0 or less, or 1 or more, an error message is printed.
CI=EQUAL
CI=UMPU
CI=NONE: specifies whether a confidence interval is displayed for $\sigma$ and, if so, what kind. The CI=EQUAL option specifies an equal tailed confidence interval, and it is the default. The CI=UMPU option specifies an interval based on the uniformly most powerful unbiased test of $H_0\colon\sigma=\sigma_0$ . The CI=NONE option requests that no confidence interval be displayed for $\sigma$ . The values EQUAL and UMPU together request that both types of confidence intervals be displayed. If the value NONE is specified with one or both of the values EQUAL and UMPU, NONE takes precedence. For more information, see the "Confidence Interval Estimation" section.
COCHRAN: requests the Cochran and Cox (1950) approximation of the probability level of the approximate t statistic for the unequal variances situation.
DATA=SAS-data-set: names the SAS data set for the procedure to use. By default, PROC TTEST uses the most recently created SAS data set. The input data set can contain summary statistics of the observations instead of the observations themselves. The number, mean, and standard deviation of the observations are required for each BY group (one sample and paired differences) or for each class within each BY group (two samples). For more information on the DATA= option, see the "Input Data Set of Statistics" section.
H0=m: requests tests against m instead of 0 in all three situations (one-sample, two-sample, and paired observation t tests). By default, PROC TTEST uses H0=0.

Chapter Contents
Previous
Next
Top