A study of bulimia among college women (J. Kern and T. Hastings, Journal of Clinical Psychology, vol. 51, 1995, p. 499) studied the connection between childhood sexual abuse and a measure of family cohesion (the higher the score, the greater the cohesion). The sample mean on the family cohesion scale was 2.0 for 13 sexually abused students (s = 2.1) and 4.8 for 17 non abused students (s = 3.2).
a. Find the standard error for comparing the means.
b. Construct a 95% confidence interval for the difference between the mean family cohesion for sexually abused students and non-abused students. Interpret.