A survey of 430 randomly chosen adults finds that 47 of 222 men and 37 of 208 women had purchased books online.
a) Is there evidence that the sex of the person and whether they buy books online are associated?
b) If your conclusion in fact proves to be wrong, did you make a Type I or Type II error?
c) Give a 95% confidence interval for the difference in proportions of buying online for men and women.