6th Grade Math Textbook, Fundamentals

Lesson 8-8 for exercise sets. &KDSWHU 

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The box-and-whisker plots at the right compare points

scored in a spelling bee by two different groups.

Use the plots for exercises 1–4.

1.What is the median number of points scored in

Ms. Stegner’s class? In Mr. Parker’s class?

2.Which class has the greater range of points scored?

3.For which class do the points scored cluster more closely around the median?

4.Discuss and Write What measure or measures of central tendency are

box-and-whisker plots most useful for showing?

(^1) Length of Time in Minutes
58 53 52 74 63 59 43 56 67 82 48
52 65 67 67 73 64 47 53 85 45

The is the difference between the upper quartile and the

lower quartile. If this difference is small, then the data in the middle of the set

are close or. If it is large, then the data in the middle of the set are

spread out and there are in the data. Gaps are places on the graph with no

data. One way to determine if there are any , or points that are clearly

separate from the set of data, is to multiply the interquartile range by 1.5.

interquartile range upper quartile lower quartile

9.2 7.2 2.0

and 1.5 • 2.0 3.0

So outliers are any data that are more than 3 points away from either quartile.

lower quartile 3.0 7.2 3.0 4.2

upper quartile 3.0 9.2 3.0 12.2

Since no points are less than 4.2 or greater than 12.2, there are no outliers.

gaps

clustered

Any data point less than 4.2 or

greater than 12.2 is an outlier.

outliers

interquartile range

12 13 14 15 16 17

Ms. Stegner’s class

Spelling Bee Scores

Mr. Parker’s class

The table shows how many minutes each of

21 students spent doing research for a project.

Use the data to make a box-and-whisker plot.

Then interpret the data.

43, 45, 47, 48, 52, 52, 53, 53, 56, 58, 59, 63, 64, 65, 67, 67, 67, 73, 74, 82, 85

There are no outliers: since 1.5 • 15 22.5; and 52 22.5 29.5 and 67 22.5 89.5.

The data set does not contain any values less than 29.5 or greater than 89.5.

40 50 60

Time Spent Doing Research

70 80 90

The median is 59. The upper quartile is 67.

The lower quartile is 52. The upper extreme is 85.

The lower extreme is 43. The interquartile

range is 15.