For each of Exercises 57–60, do the following:

  1. Find the point estimate of the population mean.
  2. Calculate .
  3. Find for a confidence interval for the indicated confidence level.
  4. Confirm that the conditions for constructing a interval are met.
  5. Construct and interpret a confidence interval with the indicated confidence level for the population mean.

Question 8.57

57. Consumption of Carbonated Beverages. The U.S. Department of Agriculture reports that the mean American consumption of carbonated beverages per year is greater than 52 gallons. A random sample of 30 Americans yielded a sample mean of 69 gallons. Assume that the population standard deviation is 20 gallons. Let the confidence level be 95%.

8.1.57

(a) 69 gallons (b) 3.65 gallons (c) (d) and the population standard deviation is known. (e) (61.84, 76.16). We are 95% confident that lies between 61.84 gallons and 76.16 gallons.