Service level is:

$q,$

something that should be minimized in retail.

the probability of not stocking out.

the probability of not stocking out and calculated as the cost of a shortage divided by $($the cost of shortage $+$ the cost of overage$)$ for single$-$period models

calculated as the cost of a shortage divided by $($the cost of shortage $+$ the cost of overage$)$ for singleperiod models.

the probability of stocking out.