HW Score: 44.05%, 9.25 of 21 points 0 Points: 0 of 1 Question 13, 6.2.31 -T Homework: Sec 6.2 Part 2 of a I e The monthly incomes for 12 randomly selected people, each with a 445053 4596.51 4366.95 i: bachelors degree In economics, are shown on the right. Complete parts 4455-45 4151.58 3727.06 (a) through (c) below. 4283.52 4527.12 4407.74 Assume the population is normally distributed. 3946.78 4023_15 422154 Question list 0 Question 9 (a) Find the sample mean. 0 Question 10 )_(= 4263.17 (Round to one decimal place as needed.) (b) Find the sample standard deviation. 0 Question 11 s = D (Round to one decimal place as needed.) x/./ Question 12 0 Question 13 0 Question 14 0 Question 15 In a random sample of 21 people, the mean commute time to work was 34.1 minutes and the standard deviation was Question list K 7.2 minutes. Assume the population is normally distributed and use a t-distribution to construct a 99% confidence interval for the population mean u. What is the margin of error of u? Interpret the results. Question 7 The confidence interval for the population mean u is ( 29.6 , 38.6 ). (Round to one decimal place as needed.) Question 8 The margin of error of u is. (Round to one decimal place as needed.) Question 9 Question 10 O Question 11 Question 12 Question 13Question list g\\" g\\" Question 7 Question 8 Question 9 Question 10 Question 11 Question 12 Question 13 I In a random sample of eight people, the mean driving distance to work was 20.6 miles and the standard deviation was 7.5 miles. Assume the population is normally distributed and use the tdistribution to nd the margin of error and construct a 99% condence interval for the population mean p. Interpret the results. Identify the margin of error. 9.3 miles (Round to one decimal place as needed.) Construct a 99% condence interval for the population mean. (DD) (Round to one decimal place as needed.) HW Score: 68.57%, 14.4 of 21 points 0 Points: 0 of 1 Question 14, 6.2.35-T Part 2 of 3 Use the standard normal distribution or the tdistribution to construct a 99% confidence interval for the population mean. Justify your decision. If neither distribution can be used, explain why. Interpret the results. In a random sample of 46 people, the mean body mass index (BMI) was 28.3 and the standard deviation was 6.13. E) Which distribution should be used to construct the condence interval? Choose the correct answer below. * Use a tdistribution because the sample is random, n 2 30, and o is unknown. Use a normal distribution because the sample is random, n 230, and a is known. Use a tdistribution because the sample is random, the population is normal, and c is unknown. 3' Use a normal distribution because the sample is random, the population is normal, and c is known. Neither a normal distribution nor a t-distribution can be used because either the sample is not random, or n