1. Data were collected on the amount spent by 64 customers for lunch at a major Houston restaurant. These data are contained in the file named Houston. Based upon past studies the population standard deviation is known with= $6.

a. At 99% confidence, what is the margin of error?

b. Develop a 99% confidence interval estimate of the mean amount spent for lunch.

2. Amazon.com is testing the use of drones to deliver packages for same-day delivery. In order to quote narrow time windows, the variability in delivery times must be sufficiently small. Consider a sample of 24 drone deliveries with a sample variance of s(squared)= .81.

a. Construct a 90% confidence interval estimate of the population variance for the weight of this drug.

b. Construct a 90% confidence interval estimate of the population standard deviation.

3. Several researchers have found that evaluating the internal control procedures of an organization by evaluating its accounting records is impractical because businesses are usually too large to allow for an examination of all, or even a quarter, of the year's transactions. An audit was conducted by randomly selecting n= 36 bills of lading from among those transacted during the past year by a trucking firm. The mean and standard deviation of the bills were found to be $2,160 and $575, respectively. Estimate _x, the average bill of lading transacted by the firm during the past year, and place a 99% bound on the error of estimation.