Topic 4.3 - Measures of center and dispersion

The mean test score for a class was 76 with a standard deviation of 5 points.

The teacher decides to add 4 points to every students test score.

What is the new mean and standard deviation for the distribution of test scores?

• mean = 80

  SD = 5

• mean = 80

  SD = 9

• mean = 76,

  SD = 5

• Cannot determine from the information given

A 50 point test had a mean of 42 with a standard deviation of 5 points.

The teacher decides to multiply all scores by 2 (so the total is out of 100).

What is the new mean and standard deviation for the distribution of test scores?

• mean = 84,

  SD = 10

• mean = 84,

  SD = 5

• mean = 42,

  SD = 5

• Cannot determine from the information given

If 30 is added to every observation in a data set, the only one of the following that is not changed is

• the mean

• the median

• the standard deviation

• the minimum

SELECT ALL that will change if you multiply all of the data by a constant

• mean

• median

• range

• IQR

• standard deviation

The table shows the number of people with the corresponding number of friends on Facebook.  What is the mean?

(Correct to three significant figures)

• 49.6
• 50
• 49.5

• 29.3

Tags

CCSS.6.SP.B.5C

The table shows the number of people with the corresponding number of friends on Facebook.  What is the median? 

• 49.6
• 50
• 49.5

• 30

• 38.5

Tags

CCSS.6.SP.B.5C

The table shows the number of people with the corresponding number of friends on Facebook.  What is the standard deviation? 

• 1.6
• 2.3
• 3.1
• 2.5

The table shows the number of people with the corresponding number of friends on Facebook.  What is the mode? 

• 49

• 50

• 49.6

• There is no mode

Tags

CCSS.6.SP.B.4

CCSS.HSS.ID.A.1

What are the mid-interval values for the distribution?

• 29, 39, 49, 59

• 29.5, 39.5, 49.5, 59.5

• 30, 40, 50, 50

• 42, 57, 72, 87

Answer explanation

You are finding the Midpoint

The mean of this data set is

• 52

• 25

• 44

• 32

Tags

CCSS.6.SP.B.5C