D = Average demand per period

sD = Standard deviation of demand (forecast error) per period

L = Average lead time - between when an order is placed and when it is received

sL = Standard deviation of lead time per order

Safety Stock (ss) = SQRT(LsD2+D2sL2) x "Z Score"

Cell-Phones-For-Less sells a large quantity of prepaid cell phones, on average 1500 per week with a standard deviation of 145. The lead time for the prepaid cell phones is five weeks with a standard deviation of two weeks. The owner continuously monitors inventory. Their typical order size is 4500 phones.

What safety stock should be held by Cell-Phones-For-Less to meet by a cycle service level (CSL) of 99%?]

Select one:

a. 4,500 phones

b. 8,225 phones

c. 7,032 phones

d. 3,018 phones