Standard Deviation

Which of the following is a measure of variability?

• mean

• median

• mode

• standard deviation

Ervin bowled 7 games last weekend. His scores are: 155, 165, 138, 172, 127, 193, 142. What is the sample standard deviation of Ervin's scores?

• 511.33

• 22.61

• 438.48

• 20.94

What is the variance for the data given:
5, 10, 7, 12, 0, 20, 15, 22, 8, 2

• 47.47

• 102.01

• 52.77

• 81

If the standard deviation of a data set is 4, what is the variance?

• 2

• 16

• 4

What is the standard deviation on this Normal Curve?

• 6

• 12

• 34

• 18

Data on the weights of various dog breeds is shown. Which of the following BEST describes what would happen to the standard deviation if the average weight of a St. Bernard, which weighs around 160 pounds, was added to the list?

• The Standard Deviation will increase.

• The Standard Deviation will decrease.

• The Standard Deviation will be unchanged.

• The Standard Deviation will be impossible to calculate.

Answer explanation

Remember, the standard deviation describes how spread out the numbers are. If a data value is added to the data set that widens the range of the data, it will always increase the standard deviation.

This is true even if a value that is LOWER than all the data is added. The standard deviation will still increase, because the range of the data is widened.

Which curve has the greater standard deviation?

• Red

• Black

• Blue

The following symbol represents what?

• the sample mean

• the population mean

• the sample standard deviation

• the population standard deviation

• the sample size

List each set of data by color from the lowest standard deviation to the highest standard deviation.

• blue, green, pink, red

• red, pink, green, blue

• pink, green, red, blue

• blue, green, red, pink

What does this symbol represent?

• Standard Deviation

• Variance

• Mean Absolute Deviation

• Sigma