After a ham is cured, it may be smoked to add flavor or to ensure it lasts longer. Typical grocery-store hams are smoked for a short period of time, whereas gourmet hams are usually smoked for at...

After a ham is cured, it may be smoked to add flavor or to ensure it lasts longer. Typical grocery-store hams are smoked for a short period of time, whereas gourmet hams are usually smoked for at least one month. A random sample of 36 grocery-store hams was obtained, and the length of the smoking time was recorded for each. The mean was x 5 140 hours. Assume s 5 8 hours.

a. Find a 99% confidence interval for the mean amount of time a grocery-store ham is smoked. Write a Solution Trail for this problem.

 b. What assumptions did you make in order to construct the confidence interval in part (a)?

 In May 2013 the manager of Chicago’s Navy Pier set the world record for the longest ferris wheel ride. Clinton Shepherd spent more than 2 days and 384 revolutions on the wheel in a specially designed gondola.9 During normal park hours, a random sample of ferris wheel riders was obtained and the length of each ride was measured (in minutes). Assume s 5 0.5.

a. Find a 95% confidence interval for the mean amount of time on this ride.

 b. Find a 99% confidence interval for the mean amount of time on this ride.

c. Explain why the interval in part (b) is wider.