a. Using the graph from Exercise 21, calculate the standard deviation Y. This gives us an idea of how much variation wed expect in the

a. Using the graph from Exercise 21, calculate the standard deviation σY. This gives us an idea of how much variation we’d expect in the employee’s expense records if he assumed that first digits from 1 to 9 were equally likely.

b. The standard deviation of the first digits of randomly selected expense amounts that follow Benford’s law is σX = 2.46 . Would using standard deviations be a good way to detect fraud? Explain your answer.

Exercise 21.

Probability for cach value = 1/9 0.3 0.2 2 - 0.1 0.0 0 1 2 3 4 5 6 7 8. 9. Outcomes Probability