The gift shop at the park sells souvenir towels and souvenir cups. towels cost $12 each and souvenir cups cost $12 each. the day the jennings were at the park, the gift shop sold 10 towels and 20 cups every hour for 5 hours.

Do one of the following, as appropriate: (a) find the critical value z subscript alpha divided by 2 , (b) find the critical value t subscript alpha divided by 2 . 99%; nequals 17; sigma is unknown; population appears to be normally distributed.