I am having trouble completing this spreadsheet. Everything from the Z score down. could you please help I am also confused with the SS formula

A B C D E F G H K L M N P Q Reorder Point with Safety Stock Compute the necessary items below to find WHEN to order! . Reorder point (ROP) calculations: But what if demand isn't constant? ROP = DD X RC under certainty But what if delivery isn't reliable?? ROP = (DD x RC) + SS under uncertainty Daily demand (average) DD = 85.81 units/day Historical Data Length of each Where DD = daily demand Standard deviation of Demand = ODD = 9.453 units/day replenishment cycle RC = length of replenishment cycle Daily Demand (units) (days) SS = safety stock 90 12 Length of replenishment cycle (average) = RC= 12.89 days 85 12 Standard deviation of Replenishment Cycle = ORC 1.269 days 11 75 11 60 13 Service level target = 96% 78 15 14 Z = 83 14 HINT: To convert Service Level to z-score, use =NORM.S.INV(probability) 15 95 13 Note: The standard normal distribution has a mean=0 and StDev=1. 16 Reorder Point without Variability = units 93 12 + 95 14 When demand is uncertain (always ) and replenishment cycle is uncertain (always ). Safety Stock (to buffer from variability) = SS = units 94 = 92 SS = ZO2DD * RC + 02 RC * DD2 Reorder Point (in the real world!) = ROP = units 83 (round to the nearest unit) 90 85 Unit Cost of items in inventory = 1= $ 15.00 per unit 95 Inventory carrying cost rate = C= 32% per year 80 25 How much does it cost to hold just the Safety Stock for 26 one year? per year 27 28 Extra: How much more would it cost to increase Safety Stock to reach a 97% Service Level? To reach 99% Service Level? 30