Please do the T$-$shirts Problem with a sales price of $$16$ and production cost of $$12.$ Unsold shirts can be sold off at $$6.$ The demand is given by N$($mu $=51,$ sigma $=10).$What is the under$-$stocking cost Cu$?$What is the over$-$stocking cost Co$?$What is the service level or critical fractile? $($Please state a probability with $4$ decimal places $($and not a percentage$)$What is the corresponding z$-$score?What is the optimal order quantity? Please round to a whole number.