A sample of 500 evening students revealed that their annual incomes were normally distributed with a mean income of $50,000 and a standard deviation of $4,000. How many students earned more than $55,000?
A) 53
B) 197
C) 303
D) 35

Question

Quizplus · Accepted Answer

To find the number of students earning more than $55,000, we calculate the z-score: z = (55000 - 50000) / 4000 = 1.25. Using the standard normal distribution table, the probability of a z-score less than 1.25 is approximately 0.8944. Therefore, the probability of earning more than $55,000 is 1 - 0.8944 = 0.1056. Thus, the number of students is 0.1056 * 500 ≈ 53.

A Sample of 500 Evening Students Revealed That Their Annual