Question 13:

Asked on October 23, 2007

Tags: Z-Score , Unusual Event

1

Answer:

No answer provided yet.Here's all you need to do. Calculate the z-score, then find the percent of area under the curve to this value or just interpret the z-score as is. So you have Tuesdays sales of $34,650.77 minus the mean 28,707.47 divided by the standard deviation of sales 1000 which equals 5943.30/1000, which equals a z-score of 5.9433.

That z alone tells you its an extreme event. Because it is a positive value it tells you it was almost 6 standard deviations above the mean (5.9433 specifically). That means more was sold on Tuesday than on 99.99999986% of all days. I'd say that's a really good sales day!