Question

A normal distribution of score has a standard deviation of 10 and a mean of 0. What is the z score of a score that is 20 points above the mean?

Answer 1

Given a Normal Distribution, you know that:

- The Standard Deviation is:

`\sigma=10`

- The Mean is:

`\mu=0`

The formula for calculating the z-score is:

`z=(X-\mu)/(\sigma)`

Where μ is the Mean and σ is the Standard Deviation.

In this case, the score is 20 points above the mean, therefore;

`X=\mu+20=0+20=20`

Therefore, by substituting values into the formula and evaluating, you get:

`z=(20-0)/(10)`
`z=(20)/(10)`
`z=2`

Hence, the answer is:

`z=2`