The state test scores for 12 randomly selected high school seniors are shown on the right. Complete parts (a) 1430 1229 987 through (c) below. 700 728 832 720 746 547 Assume the population is normally distributed. 626 1448 942 . . . (b) Find the sample standard deviation. s = 305.6 (Round to one decimal place as needed.) (c) Construct a 99% confidence interval for the population mean p. A 99% confidence interval for the population mean is ( (Round to one decimal place as needed.)