On a standardized exam, the scores are normally distributed with a mean of 350 and a standard deviation of 40. Find the Z-score of a person who scored 346 on the exam.

Step-by-step explanation:

A z-score helps describe the relationship between a value and the mean of a group of values. Basically, it tells us how many standard deviations away from the mean a value is. The formula is:

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

For this standardized exam, the mean is 350 and the standard deviation is 40. We want to find the z-score for a value of 346.

Substitute the values into the formula.

Solve the numerator.

Divide.

The z score is -0.1, so the person with a score of 346 on the exam was 0.1 standard deviations lower than the mean.

well, because the $0.25 is an added cost depending on how many minutes, the answer would be y = 30 + 0.25x.