Question

A department store, on average, has daily sales of 28,651.79. the standard deviation pf sales is $1000. On Tuesday, the store sold $36,211.08 worth of goods. Find Tuesday's Z-score. Was Tuesday an unusually good day?

Answer 1

Answer:

Tuesday's Z-score is 7.56

Step-by-step explanation:

We are given that a department store, on average, has daily sales of 28,651.79 and the standard deviation of sales is $1000.

Also, it is given that on Tuesday, the store sold $36,211.08 worth of goods.

Let X = Daily sales of goods

So, X ~ N($\mu = 28,651.79, \sigma^{2} =1000^{2}$)

The z-score probability distribution is given by;

        Z = $\frac{X-\mu}{\sigma}$ ~ standard normal N(0,1)

Now, Tuesday,s Z-score is given by;

      Z = $\frac{36,211.08-28,651.79}{1000}$ = 7.56

Yes, Tuesday was an unusually good day as on this day more worth of sales takes place as compared to the average daily sales of $28,651.79 .