please answer ALL PARTS to the questions A-D thanks!

The average licensed driver travels 1,147 miles per month in his or her vehicle. Assume the population standard deviation is 294 miles per month. Determine the interval that will contain 87% of the sample means for the sample sizes in parts a through c. a. 30 drivers b. 50 drivers c. 70 drivers d. Explain the differences in these probabilities a. Using a sample size of 30 the lower bound of the symmetrical interval is and the upper bound is (Type an integer or decimal rounded to one decimal place as needed.)