The random sample shown below was selected from a normal distribution. 3, 7, 6, 7, 5, 8 Complete parts a and b. . . . a. Construct a 99% confidence interval for the population mean u. ( 3.06 , 8.94 ) (Round to two decimal places as needed.) b. Assume that sample mean x and sample standard deviation s remain exactly the same as those you just calculated but that are based on a sample of n = 25 observations. Repeat part a. What is the effect of increasing the sample size on the width of the confidence intervals? The confidence interval is (Round to two decimal places as needed.)