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The TTEST Procedure |

**PROC TTEST***< options >***;**

**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 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
. The CI=NONE option requests that no confidence interval
be displayed for . 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.

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