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 [tex]\mu=500[/tex]
Standard deviation: [tex]\sigma=100[/tex]
Let x be a random variable to represent the data values .
The formula for z-score :-
[tex]z=\dfrac{x-\mu}{\sigma}[/tex]
For x=225, we have
[tex]\Rightarrow\ z=\dfrac{225-500}{100}=-2.75[/tex]
Hence, the z-score of 225 point score =-2.75
