Review: Standard Deviation, Z-Scores, and Percentages

Where are most data points located in a normal distribution?

• Close to the mean

• Two standard deviations from the mean

• Three standard deviations from the mean

• All data is close to the mean

If multiple sets of data have the same mean, then they have the same standard deviation.

• True

• False

A sample data set has mean of 45 and standard deviation of 8. What is -1 standard deviation from the mean?

• 45

• 53

• 37

• 38

A data set has a mean of 95 and a standard deviation of 12. Find -3 standard deviations from the mean.

What percent of data should fall within one standard deviation above the mean (positive)?

What percent of data should fall within two standard deviations below and above the mean?

• 34%

• 68%

• 95%

• 99.7%

What is the z-score if the standard deviation is 5, the mean is 40, and the value is 45?

• -5

• 5

• -1

• 1

What is the z-score if the standard deviation is 10, the mean is 50, and the value is 30?

What is the Z-Score if the standard deviation is 10, the mean is 50, and the value is 65?

• -2

• 1.5

• 15

• -15

What is the Z-Score if the standard deviation is 5, the mean is 70, and the value is 72.5?