Measures Spread

Find the median, first quartile, third quartile, and interquartile range of the data.

32, 53, 72, 66, 47, 54, 49, 67, 71

• Median: 54

  First Quartile: 49

  Third Quartile: 67

  IQR: 18

• Median: 54

  First Quartile: 48

  Third Quartile: 69

  IQR: 21

• Median: 54

  First Quartile: 48

  Third Quartile: 69

  IQR: 22

• Median: 54

  First Quartile: 49

  Third Quartile: 69

  IQR: 20

What is the range?

• average

• biggest-smallest

• the middle #

• happening the most

If a number is added to the set that is in the middle of the data, how does this affect the range?

• increase

• decrease

• stay the same

• both increase and decrease

Which measure of spread should be used to describe the distribution?

• standard deviation

• interquartile range

• range

• median

Which summary statistic should be used to compare the two data sets and why?

• The median and the interquartile range because they are normally distributed.

• The median and the interquartile range because they are skewed.

• The mean and the standard deviation because they are normally distributed.

• The mean and the standard deviation because they are skewed.

Which of the following is a measure of variability?

• mean

• median

• mode

• standard deviation

Find the range of the data.

63, 71, 65, 66, 87, 53

• 32

• 33

• 34

• 35

Given the data: 136, 150, 119, 150, 125, 140.
Find the upper quartile (Q3). (Hint... put the numbers in order and find the median to help you find Q3)

•  125

• 150

• 139.5

• 143

Calculate the interquartile range of the following data17, 18, 18, 19, 20, 21, 21, 23, 25

• 3

• 4

• 5

• 8

What is the standard deviation for the data given:
{12, 13, 29, 18, 61, 35, 21}

• 293.67

• 15.87

• 17.14

• 41.98