For a local pub, they are seeking to achieve a service level of $0\mathrm{.}91.$ The order interval is $11$ days, and the

lead time is $24$ hours. Demand for beers is $63$ per day with a standard deviation of $5$ per day. They

currently have $71$ beers on hand at reorder time.

a$)$ What is the z$-$value?

b$)$ Determine the number of beers the local pub should order, i$.$e$.,$ the amount to order