QUESTION $4$

Consider the case when Sony uses a Periodic Review Policy $($I$,$ S$).$ Sony plans to order from its supplier once in fourteen business days, corresponding to a Review Period of I $=14$ business days. The supplier delivers each order in a lead$-$time of $6$ business days. Sony has an expected $($average$)$ daily demand of $150$ units with a standard deviation $($of daily demand$)$ of $30$ units. The management team at Sony continues to target a $93\%$ service level. What is the appropriate safety stock $($SS$)?$