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
