Find the indicated probability.
-The weekly salaries of teachers in one state are normally distributed with a mean of $490 and a standard deviation of $45. What is the probability that a randomly selected teacher earns more than $525 a week?
A) 0.2177
B) 0.2823
C) 0.1003
D) 0.7823

Question

Quizplus · Accepted Answer

We need to find the probability of a teacher earning more than $525 a week. First we standardize the value using the formula z = (x - μ) / σ where x is the value ($525), μ is the mean ($490) and σ is the standard deviation ($45). 
z = (525 - 490) / 45 = 0.7778
Using a standard normal table or calculator, the probability of getting a value greater than 0.7778 is approximately 0.2177. So the answer is choice A.

Find the Indicated Probability