A student scores 85 on a test with a mean of 75 and a standard deviation of 5. Find the student's z-score.

Step 1: Recall the z-score formula.

z = (x - μ) / σ

where x is the individual value, μ is the mean, and σ is the standard deviation.

Step 2: Identify the given values.

x = 85
μ = 75
σ = 5

Step 3: Substitute the values into the formula.

z = (85 - 75) / 5

Step 4: Simplify.

z = 10 / 5
z = 2

Step 5: Interpret the result.

A z-score of 2 means the student's score is 2 standard deviations above the mean.

Therefore, the student's z-score is 2.