Measures of Center and Measures of Spread

The numbers of runs scored by a softball team in 20 games are given.
 3, 4, 8, 12, 7, 5, 4, 12, 3, 9, 11, 4, 14, 8, 2, 10, 3, 10, 9, 7
What is the Interquartile Range.

• IQR = 6

• IQR = 10

• IQR = 7.5

• IQR = 12

The first quartile (Q 1) is the median of the lower half of the set.
The second quartile (Q 2) is the median of the whole set .
The third quartile (Q 3) is the median of the upper half of the set.

• All three statements are true.

• Only the 1st statement is true.

• Only the 2nd and the 3rd statements are true.

• Only the 3rd statement is true.

Standard Deviation is a measure of spread, which represents the average of the distance between individual data values and the mean.

• True

• False

Given the data: 21, 31, 26, 24, 28, 26
This is a 3 part question:
Part-1: What is the mean of the data?

• 24

• 25

• 26

• 27

Given the data: 21, 31, 26, 24, 28, 26
This is a 3 part question:
Part-2: Find the standard deviation of 21, 31, 26, 24, 28, 26.

• S.D. ≈ 9.67

• S.D. ≈ 26

• S.D. ≈ 3.1

• S.D. ≈ 10

Given the data: 136, 150, 119, 150, 125, 143.
Find the range. 

• Range = 136 - 125 = 21.

• Range = 150 - 125 = 75.

• Range = 150 - 125 = 25.

• Range = 150 - 119 = 31

Given the data: 136, 150, 119, 150, 125, 143.
Find the interquartile range (IQR)

•  IQR = 150 - 119 = 31

•  IQR = 150 - 125 = 25.

• IQR = 150 - 125 = 75.

•  IQR = 150 - 119 = 31.

• Mode
• Median
• Mean
• IQR

• 13.6
• 2.2
• 15.8
• 68.2

Quartiles are values that divide a data set into four equal parts.

• True

• False