b$.$ If the copy center reorders when the supply on hand is $13$ boxes, compute the risk of a stockout $($Round $"z"$ volue to $2$ decimal places and final answer to $4$ decimal places.$)$

c$.$ If a fixed interval of $8$ weeks is used for ordering instead of an ROP, how many boxes should be ordered if there are currently $25$ boxes on hand, and an acceptable stockout risk for the order cycle is $\mathrm{.}0228?($Round $"z"$ value to $2$ decimal places and final answer to the nearest whole number.$)$

Q $0$