Solution to Exercise 7.28.

  Straight table look-ups from Table A.5, p. 725 (yawn).

(a) t_.1,15 = 1.341

(b) t_.05,15 = 1.753

(c) t_.05,25 = 1.708

(d) t_.05,40 = 1.684

(e) t_.005,40 = 2.704