8.1 - Measures of Spread

Use the 1.5 IQR rule to determine if there are any outliers for the following numbers: 84, 88, 72, 74, 98, 16, 94 

The 5 number summary is given.

Low Outlier(s):​ (a)  

High Outliers:​ (b)  

• 16
• No Low Outliers
• No High Outliers
• 98
• 98 and 94
• 98, 94 and 88
• 98, 94, 88 and 84

• The data has an outlier, 3.05 inches.

• The standard deviation is 0.9114

• The IQR is 0.961

• The median is 5.355

• The data has no outliers

The number of dog owners who signed up for dog obedience classes for the last 11 months were 21, 24, 18, 25, 26, 23, 10, 24, 38, 15, and 18. Identify the outlier. Which statements are true? Select all that apply.

• 10 is an outlier

• 38 is an outlier

• The median is 23

• The mean is 23

• The standard deviation is 6.85

The golf coach wants to compare the students’ scores at the end of the season with their scores at the beginning of the season. What is the mean and standard deviation of the data at the beginning of the season?

• Mean: 80; Standard Deviation: 2.6

• Mean: 80; Standard Deviation: 3.1

• Mean: 82; Standard Deviation: 2.5

• Mean: 82; Standard Deviation: 2.8

The golf coach wants to compare the students’ scores at the end of the season with their scores at the beginning of the season. What is the mean and standard deviation of the data at the end of the season?

• Mean: 79;

  Standard Deviation: 2.5

• Mean: 79;

  Standard Deviation: 2.8

• Mean: 81;

  Standard Deviation: 2.6

• Mean: 81;

  Standard Deviation: 2.2

Zip codes are numerical designations of locations for the purpose of mail delivery. The following histogram summarizes the number, in hundreds, of zip codes assigned to each state in the United States. How many high outliers are there in the data set?

• 0

• 1

• 2

• 3

The following dotplot shows the number of songs on each album in your collection. Each dot represents a different album. How many outliers are there in the data set?

• 0

• 1

• 2

• 3

The following dotplot shows the centuries during which the 11 castles whose ruins remain in Somerset, England were constructed. Each dot represents a different castle. How many outliers are there in the data set?

• 0

• 1

• 2

• 3

The following dotplot shows the number of e-mails that you deleted each day. Each dot represents a different day. How many outliers are there?

• 0

• 1

• 2

• 3

• 0%

• 25%

• 50%

• 75%

• 100%