7th Grade Math

500 Statistical Displays

Analyze Data

SCIENCE The table shows a set of scores on a Room

A

Room

B

72 63

100 93

67 79

84 83

65 98

78 87

92 73

87 81

80 65

science test in two different classrooms. Compare

and contrast their measures of variation.

Find the measures of variation for both rooms.

Room A Room B

Range 100 - 65 = 35 98 - 63 = 35

Median 80 81

UQ _^87 +^92

2

= 89.5 _^87 +^93

2

= 90

LQ _^67 +^72

2

= 69.5 _^65 +^73

2

= 69

Interquartile

Range

89.5 - 69.5 = 20 90 - 69 = 21

Both classrooms have a range of 35, but Room B has an interquartile

range of 21 while Room A’s interquartile range is 20. There are slight

differences in the medians as well as upper and lower quartiles.

c. WEATHER Temperatures for the

Month Antelope, MT Augusta, ME

January 21 28

February 30 32

March 42 41

April 58 53

May 70 66

June 79 75

first half of the year are given

for Antelope, Montana, and

Augusta, Maine. Compare and

contrast the measures of

variation of the two cities.

Examples 1 and 2 1. WIND SPEED The average wind (^) Wind Speed
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speeds for several cities in
Pennsylvania are given in the table.
a. Find the range of the data.
b. Find the median and the upper and
lower quartiles.
c. Find the interquartile range.
d. Identify any outliers in the data.
Example 3 2. TREES The heights of several types of
palm trees, in feet, are 40, 25, 15, 22, 50,
and 30. The heights of several types of
pine trees, in feet, are 60, 75, 45, 80, 75, and 70. Compare and contrast
the measures of variation of both kinds of trees.
498_509_C09_L2_895130.indd 500 1/11/10 9:34 AM