Shopping on Black Friday. Refer to the International Journal of Retail and Distribution Management (Vol. 39, 2011) survey of Black Friday shoppers, Exercise 7.22

(p. 353). One question was “How many hours do you usually spend shopping on Black Friday?”

a. How many Black Friday shoppers should be included in a sample designed to estimate (with 95% confidence)

the average number of hours spent shopping on Black Friday if you want the estimate to deviate no more than .5 hour from the true mean?

b. Devise a sampling plan for collecting the data that will likely result in a representative sample.