Assume that the amount of time that it takes an employee to service a car at an oil change facility follows the uniform probability distribution between 21 and 38 minutes.

What is the standard deviation of this distribution

a. 4.91

b. 6.62

c. 9.75

d. 11.8

Option A - 4.91

Step-by-step explanation:

The formula for theoretical standard deviation of uniform distribution is;

σ = √{ (b-a) ^2}/12

Now from the question, b = 38 minutes and a = 21 minutes

Therefore, σ = √{ (38-21) ^2}/12

= √{17^2}/12 = √289/12 = 4.907 which is approximately 4.91