Two-sample t test with equal variances Obs Mean Std. err. Std. dev. [95% conf. interval] X 23 41. 52174 3. 575757 17. 14873 34. 10607 48 . 93741 K 21 51. 47619 2. 402003 11. 00736 46. 4657 56 . 48668 Combined 44 46. 27273 2 . 296786 15 . 23515 41 . 64082 50 . 90464 diff -9. 95445 4. 391892 -18.81765 -1. 091252 diff = mean (x) - mean(y) t= -2. 2666 HO: diff = 0 Degrees of freedom = 42 Ha: diff 0 Pr(T |t| ) = 0. 0286 Pr(T > t) = 0.9857