On a standardized exam, the scores are normally distributed with a mean of 300 and a standard deviation of 20. Find the z-score of a person who scored 320 on the exam.

To find the z-score, we use the formula:

z = (X - µ) / σ

Where:
X = score of the person
µ = mean of the distribution
σ = standard deviation of the distribution

Plugging in the values X = 320, µ = 300, and σ = 20, we get:

z = (320 - 300) / 20
z = 20 / 20
z = 1

Therefore, the z-score of a person who scored 320 on the exam is 1.