According to the University of Nevada Center for Logistics Management, 6% of all merchandise

sold in the United States gets returned (BusinessWeek, January 15, 2007). A

Houston department store sampled 80 items sold in January and found that 12 of the items

were returned.

a. Construct a point estimate of the proportion of items returned for the population of

sales transactions at the Houston store.

b. Construct a 95% confidence interval for the porportion of returns at the Houston store.