Finding z-scores

Front

What is a z-score?

Back

A z-score indicates how many standard deviations an element is from the mean of a distribution.

Front

What is the formula for calculating a z-score?

Back

Front

If a weight of wallabies is normally distributed with a mean of 9lbs and a standard deviation of 1.5lbs, what weight corresponds to a z-score of -2?

Back

6lbs.

Front

How do you interpret a positive z-score?

Back

A positive z-score indicates that the value is above the mean.

Front

How do you interpret a negative z-score?

Back

A negative z-score indicates that the value is below the mean.

Front

A student scores 75% in chemistry with a z-score of 2.34. What does this imply about her performance?

Back

She performed significantly better than her peers in chemistry.

Front

What does a z-score of 0 indicate?

Back

A z-score of 0 indicates that the value is exactly equal to the mean.

Front

If a student scores 28 on the ACT, which has a mean of 21 and a standard deviation of 5, what is the z-score?

Back

The z-score is 1.40.

Front

If a student scores 31 on the ACT, what is the z-score?

Back

The z-score is 2.00.

Front

What does a z-score of 2.00 indicate about a student's ACT score?

Back

It indicates that the student's score is 2 standard deviations above the mean.