Interactive Classroom

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Lesson Menu
Main Idea and New Vocabulary Key Concept Using
Mean, Median, and Mode Example 1 Choose an
Appropriate Measure Example 2 Choose the
Appropriate Measure Example 3 Choose the
Appropriate Measure Example 4 Choose the
Appropriate Measure
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Main Idea/Vocabulary

• Choose an appropriate measure of central
  tendency. Identify outliers.

• outlier

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Key Concept
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Example 1
Choose an Appropriate Measure
SEA TURTLES The table shows the total number of
sea turtles observed at four sea turtle research
sites on the eastern coast of Florida. Which
measure of central tendency best represents the
data? Find that measure of central tendency.
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Example 1
Choose an Appropriate Measure
Since the set of data has an extreme value, 207,
and no repeated values, the median would best
represent the data.
207 1,033 1,231 1,332
Answer The median number of sea turtles
observed is 1,132.
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Example 1 CYP
SANDWICHES The prices of several sandwiches are
4.50, 4.75, 4.50, 4.25, 4.50, 4.50, 5.75,
and 4.75. Which measure of central tendency best
represents the data? Find that measure of central
tendency.
A. mean 4.69 B. median 4.38 C. mode
4.75 D. mode 4.50
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Example 2
Choose the Appropriate Measure
ANIMALS The table shows the number of threatened
species in the United States in 2005. Identify
the outlier in the data set.
Compared to the other values, 43 is extremely
high.
Answer So, the outlier is 43.
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Example 2 CYP
WEATHER The daily high temperatures for one week
were 78, 75, 53, 75, 79, 83, and 76.
Identify the outlier in the set.
A. 53 B. 75 C. 78 D. 83
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Example 3
Choose the Appropriate Measure
ANIMALS The table shows the number of threatened
species in the United States in 2005. Determine
how the outlier affects the mean, median, and
mode of the data.
Find the mean, median, and mode with and without
the outlier.
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Example 3
Choose the Appropriate Measure
With the outlier
Median 11 Mode 9 and 11
Without the outlier
Median 10 Mode 9 and 11
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Example 3
Choose the Appropriate Measure
Answer The mean decreased by 15 10 or 5. The
median decreased by 1. The mode did not change.
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Example 3 CYP
WEATHER The daily high temperatures for one week
were 78, 75, 53, 75, 79, 83, and 76.
Determine how the outlier affects the mean,
median, and mode of the data.
A. mean decreased by about 3.5 median
increased by 1 mode no change B. mean
increased by about 3.5 median increased by 1
mode no change C. mean increased by about 3.5
median decreased by 1 mode no change D. mean
decreased by about 3.5 median no change mode
no change
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Example 4
Choose the Appropriate Measure
ANIMALS The table shows the number of threatened
species in the United States in 2005. Which
measure of central tendency best describes the
data with and without the outlier?
The mean with the outlier is 15 and without the
outlier is 10.
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Example 4
Choose the Appropriate Measure
The median with the outlier is 11 and without the
outlier is 10. The modes were 9 and 11 both with
and without the outlier. The mean was affected
the most with the outlier. The median changed
very little with and without the outlier. The
modes do not describe the data very well since
there were only two repeated numbers.
Answer The median best describes the data
sinceit changed very little with and without
theoutlier.
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Example 4 CYP
WEATHER The daily high temperatures for one week
were 78, 75, 53, 75, 79, 83, and 76. Which
measure of central tendency best describes the
data with and without the outlier? Justify your
selection.
A. The mean best describes the data because it
changed very little with and without the outlier.
B. The median best describes the data because it
changed very little with and without the outlier.
C. The mode best describes the data because
there are two repeated numbers.
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