nent K Part 1 of 3 A consumer organization wants to estimate the actual tread wear index of a brand name of tires that claims graded 150 on the sidewall of the tire A random sample of n 24 indicates a sample mean tread wear index of 135 8 and a sample standard deviation of 20 2 Complete parts a through c a Assuming that the population of tread wear indexes is normally distributed construct a 99 confidence interval estimate of the population mean tread wear index for tires produced by this manufacturer unde this brand name s s Round to two decimal places as needed