On a standardized exam, the scores are normally distributed with a mean of 80 and a standard deviation of 20. Find the z-score of a person who scored 90 on the exam.
To find the z-score, you can use the formula:
\[ z = \frac{x - \mu}{\sigma} \]
Where:
- \( x = 90 \) (score of the person)
- \( \mu = 80 \) (mean of the exam scores)
- \( \sigma = 20 \) (standard deviation of the exam scores)
Plug in the values:
\[ z = \frac{90 - 80}{20} = \frac{10}{20} = 0.5 \]
Therefore, the z-score of a person who scored 90 on the exam is 0.5.