Question

The scores on a statistics exam have a normal distribution and have a mean of 99 and a standard deviation of 11. One individual’s score is 128. Find the z-score of this value.

Answer 1

2.64

Explanation:

The z score is calculated as

z=(x-mean)/Sd

The mean of scores of statistics exam=μ=99

The standard deviation of scores of statistics exam=σ=11

Individual's score in statistics exam=x=128

z=128-99/11=29/11=2.64

Hence, the z score of individual score is 2.64.