Mastering Z Scores

If the mean of a dataset is 50 and the standard deviation is 5, what is the z score for a data point of 60?

• A) 1

• B) 2

• C) 10

• D) 0.2

A z score of 0 indicates that the data point is:

• A) Exactly at the mean

• B) One standard deviation above the mean

• C) One standard deviation below the mean

• D) The minimum value in the dataset

What does a negative z score signify?

• A) The data point is above the mean

• B) The data point is below the mean

• C) The data point is exactly at the mean

• D) The data point is an outlier

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CCSS.HSS.ID.A.4

If a data point's z score is +2.5, this means the data point is:

• A) 2.5 standard deviations above the mean

• B) 2.5 standard deviations below the mean

• C) 2.5 times the mean

• D) 25% above the mean

To calculate a z score, you need:

• A) Only the mean of the dataset

• B) Only the standard deviation of the dataset

• C) Both the mean and the standard deviation of the dataset

• D) The entire dataset

What is the z score for a data point that is exactly at the mean of the dataset?

• A) 0

• B) 1

• C) It cannot be determined

• D) The mean of the dataset

If the mean of a dataset is 120 and the standard deviation is 15, what is the z score for a data point of 150?

• A) 1

• B) 2

• C) 0

• D) -2

A z score tells you:

• A) How many data points are in a dataset

• B) How many standard deviations a data point is from the mean

• C) The exact value of the mean

• D) The exact value of the standard deviation

If a dataset has a mean of 200 and a standard deviation of 10, what is the z score of a data point that is 220?

• A) 0.2

• B) 2

• C) 20

• D) 0.02

Which of the following z scores indicates the strongest deviation from the mean?

• A) -1.5

• B) 0.5

• C) 1.2

• D) -2.3