Consumer Reports uses a $100-$point customer sat$-$ isfaction score to rate the nations major chain stores. Assume that from past experi$-$ ence with the satisfaction rating score, a population standard deviation of $!=12$ is expected. In $2012,$ Costco, with its $432$ warehouses in $40$ states, was the only chain store to earn an outstanding rating for overall quality. A sample of $15$ Costco customer satisfaction scores follows.