Finding Variance and Standard Deviation

Order the dot plots from least to greatest standard deviation.

• A, D, C, B

• B, C, D, A

• A, D, B, C

• B, C, A, D

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

In a population of five university students with GPAs of 2.5, 2.3, 1.7, 1.4, and 1.1, a sample of three students are considered. What would be the standard deviation of the resulting sampling distribution?

• 0.53

• 0.41

• 0.35

• 0.22

What does variance represent?

• How many different variations are in the data set.

• How the population varies compared to the sample.

• How spread out each data value is from the mean.

• The range, but with a bunch of other stuff going on.

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

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.

the square of this value will give the variance

• standard deviation

• variance

• mean

• median

Using the previous items you have answered, what is the standard deviation?

• 1.04

• 2.90

• 8.41

• 9.50

They describe the amount of spread in a distribution.

• mode

• variance

• standard deviation

• median