Question

Suppose you have a normally distributed set of data pertaining to a standardized test. The mean score is 500 and the standard deviation is 100. What is the z-score of 225 point score?

Answer 1

$z=\dfrac{225-500}{100}=-2.75$

Answer 2

Answer: -2.75

Step-by-step explanation:

Given : We have a normally distributed set of data pertaining to a standardized test.

The mean score is $\mu=500$

Standard deviation: $\sigma=100$

Let x be a random variable to represent the data values .

The formula for z-score :-

$z=\dfrac{x-\mu}{\sigma}$

For x=225, we have

$\Rightarrow\ z=\dfrac{225-500}{100}=-2.75$

Hence, the z-score of 225 point score =-2.75