Eating disorder study. The ‘‘fear of negative evaluation'' (FNE) scores for 11 female students known to suffer from the eating disorder bulimia and 14 female students with normal eating habits,, are reproduced below. (Recall that the higher the score, the greater the fear of negative evaluation.)

(a) Find a 95% con?dence interval for the difference between the population means of the FNE scores for bulimic and normal female students. Interpret the result.

(b) What assumptions are required for the interval of part a to be statistically valid? Are these assumptions reasonably satis?ed? Explain.