Question

Suppose the scores on an exam are normally distributed with a mean μ = 75 points, and standard deviation σ = 8 points. Suppose that the top 4% of the exams will be given an A+. In order to be given an A+, an exam must earn at least what score?

Answer 1

89.008

Explanation:

z = (x– mean)/ standard deviation

x = z * standard deviation + mean

Now, z value for the top 4% of the exams (which is the same as getting a score below the 96%) has to be found using a z table.

In this case z = 1.751

x = 1.751 * 8 + 75

x = 89.008