. ttesti 16 30.313 4.7583 10 32.012 8.878

Two-sample t test with equal variances
------------------------------------------------------------------------------
         |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       x |      16      30.313    1.189575      4.7583    27.77748    32.84852
       y |      10      32.012     2.80747       8.878    25.66106    38.36294
---------+--------------------------------------------------------------------
combined |      26    30.96646    1.281078    6.532243    28.32803    33.60489
---------+--------------------------------------------------------------------
    diff |              -1.699     2.66506               -7.199414    3.801414
------------------------------------------------------------------------------
    diff = mean(x) - mean(y)                                      t =  -0.6375
Ho: diff = 0                                     degrees of freedom =       24

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.2649         Pr(|T| > |t|) = 0.5298          Pr(T > t) = 0.7351