Standard Deviation and Variance Empirical Rule

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

How do you calculate the standard deviation?

• Divide the variance by 2.

• Its a long process and I can't explain it right now.

• Find the mean and multiply it by the variance.

• Take the square root of the variance.

Before you can begin calculating the variance, you must first:

• find the mean

• find the median

• find the mode

• find the range

All of the below sets have the same mean.
Set 1-Standard Deviation=3.1
Set 2-Standard Deviation=4.9
Set 3-Standard Deviation=1.7
Set 4-Standard Deviation=3.2
Which set of data probably has the points closest to the mean?

• 1

• 2

• 3

• 4

What is the difference between the formulas for population variance and sample variance?

• The sample variance is the square root of the population variance.

• The population variance divides the sum of the squares by n-1, while sample divides by N.

• The population variance divides the sum of the squares by N, while sample divides by n-1.

• There is no difference.

In the diagram, the shaded area represents approximately 95% of the scores on a standardized test. If these scores range from 78 to 92, which could be the standard deviation?

• 3.5

• 7.0

• 14.0

• 20.0

In the diagram, about 68% of the scores fall within the shaded area, which is symmetric about the mean. The distribution is normal and scores in the area range from 50 to 80. What is the standard deviation of the scores in this distribution?

• 7.5

• 15

• 30

• 65

On a standardized test, Cathy had a score of 74, which was exactly 1 standard deviation below the mean. If the standard deviation for the test is 6, what is the mean score for the test?

• 68

• 71

• 77

• 80

On a standardized test, a score of 82 falls exactly 1 standard deviation below the mean. If the standard deviation for the test is 4, what is the mean score for the test?

• 78

• 80

• 84

• 86

On a standardized test, Phillip scored 84, exactly 1 standard deviation above the mean. If the standard deviation for the test is 6, what is the mean score for the tes?

• 72

• 78

• 84

• 90