With the plan to develop a chain of boutique pet supply stores, you have obtained data on pet

ownership among residents of Chicago's Gold Coast. You are interested in the percentage of

households in that area that own at least one pet. Within a random sample of 300 households, 30 of

the households own exactly one pet, and 12 households own two or more pets. The rest own none.

a) What is your estimate of the percentage of Blue Coast households that own at least one pet? (2

points)

b) What is the 90% confidence interval for this estimate? (Note: either provide the actual interval

or (if you are not using Excel) rigorously and completely explain how you would obtain all of

the numerical values needed to compute the interval.