Holiday Gift shop places orders for Christmas items during a trade show in July. One item to be ordered is a dated sterling silver tree ornament. Each ornament costs $$60$ when ordered in July. The ornaments will sell for $$100.$ Ornaments unsold by Christmas will be on clearance with a $60\%$ off and always sell during January.$$The best estimate for demand is:$$Demand$708090100$Probability $($PDF$)0\mathrm{.}20\mathrm{.}30\mathrm{.}30\mathrm{.}2$CDF$$a$)$ What is the mean demand? $($Hint: sum up all $\backslash$times Pr$(=).)$b$)$ What is the newsvendor critical ratio?$$c$)$ What is the optimal number of ornament Q$*$ to order?