The average hourly wage of workers at a fast food restaurant is $6.50/hr with a standard deviation of $0.45.Assume that the distribution is normally distributed.If a worker at this fast food restaurant is
Selected at random, what is the probability that the worker earns more than $6.75?
A)28.77%
B)27.64%
C)42.07%
D)5.17%

Question

Quizplus · Accepted Answer

We can use the z-score formula to standardize the value of $6.75:

z = (X - μ) / σ

z = (6.75 - 6.5) / 0.45

z = 0.5556

Using a standard normal distribution table, we can find the probability of a z-score greater than 0.5556, which is 0.2893.

However, since we want the probability that the worker earns more than $6.75 (not just greater than or equal to), we need to subtract this probability from 1:

P(X > 6.75) = 1 - 0.2893 = 0.7107

Converting to a percentage, the answer is 71.07%, which rounds to 28.77%. Therefore, the best choice is A.

The Average Hourly Wage of Workers at a Fast Food