You have joined the supply chain group at Dog Co - the leading dog supplies and food store operating in the United States. You discover that prior to your arrival all inventory and stocking decisions were being made on just the average weekly demand. The distribution of the demand was being tracked, but it was not being used at all in any of the inventory calculations.

Your manager, Hank, however, does not think you need to consider the distribution of demand. "The average has always been good enough for me!" he proclaims often and loudly. He prefers to use the average demand and then add in 10% on top, "Just to be safe". This is known as "Hank's Rule" at Dog Co.

You do not want to get fired, but you would like to demonstrate to Hank that the distribution of demand does matter and perhaps "Hank's Rule" should be changed.

Using the same two SKUs, you want to see how Hank's Rule applies to each of the products and how it impacts the probability of stocking out.

A) What is the probability that the weekly demand for the Wilson Chew Toys (only one SKU not both) will exceed the level set by Hanks Rule, that is setting the inventory level at 688 (= 625 + 62.5)?

B) What is the probability that the weekly demand for the Dexter Delights Dog Treats will exceed the level set by Hanks Rule, that is setting the inventory level at 693 (= 630 + 63)?