Weekly demand for smartphones at an Apple store is normally distributed, with a mean of 500 and a standard deviation of 300. Foxconn, the assembler, takes four weeks to supply an Apple order. Apple is targeting a CSL of 95 percent and monitors its inventory continuously. How much safety inventory of cell phones Chopra, Sunil. Supply Chain Management (What's New in Operations Management) (p. 346). Pearson Education. Kindle Edition.