If Joe scored 25 on a test with a mean of 20 and a standard deviation of 5, what is his z-score?Choose one25+1.00.0cannot be determined

1. Break Down the Problem

To calculate the z-score, we need to know:

• The raw score (Joe's score)
• The mean of the test scores
• The standard deviation of the test scores

2. Relevant Concepts

The formula to calculate the z-score is:

$z = \frac{(X - \mu)}{\sigma}$

Where:

• $z$ = z-score
• $X$ = raw score (Joe's score)
• $\mu$ = mean score
• $\sigma$ = standard deviation

3. Analysis and Detail

From the problem:

• $X = 25$
• $\mu = 20$
• $\sigma = 5$

Now substituting the values into the z-score formula:

$z = \frac{(25 - 20)}{5}$

Calculating:

$z = \frac{5}{5} = 1$

4. Verify and Summarize

The z-score calculation is correct as all values are accurately substituted and calculated.

Final Answer

Joe's z-score is $\boxed{1}$.