4. A simple random sample of 25 recent graduates from a particular collage gives a sample mean starting salary of $24,000 with sample standard deviation $3,000. (a) Give the 95% condence interval. (b) Without doing any calculations, would the 99% condence interval be narrower or wider than the 95% condence interval. (0) Suppose the sample size was 50 (instead of 25) and the sample mean and standard deviation were the same values. Without doing any calculations, would the 95% con dence interval with n = 50 be narrower or wider than the 95% condence interval with n=25