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1.A 2.B 3.C 4.D Five Minute Check 1 (over Lesson 8-2) A.15; 15.1; none B.15; 15.1; 15 C.15; 15; 15.1 D.15.1; 15; none Find the mean, median, and mode for the set of data. Round to the nearest tenth if necessary. 13, 17, 11, 12, 20, 14, 18, 16

Lesson Menu Main Idea and Vocabulary Example 1:Display Data in a Stem-and-Leaf Plot Example 2:Describe Data Example 3:Effect of Outliers

Main Idea/Vocabulary stem-and-leaf plot – data organized from least to greatest Leaf – Digits of the least place value Stem – next place value digits (not the least) Display and analyze data in a stem-and-leaf plot (2.6.8A) (M7.E.2.1.1).

Example 1 Display Data in a Stem-and-Leaf Plot BASEBALL The table below shows the number of home runs that Babe Ruth hit during his career from 1914 to Make a stem-and-leaf plot of the data. Source: baberuth.com

Example 1 Display Data in a Stem-and-Leaf Plot Step 1The digits in the least place value will form the leaves and the remaining digits will form the stems. In this data, 0 is the least value, and 60 is the greatest. So, the ones digit will form the leaves, and the tens digit will form the stems. Step 2 List the stems 0 to 6 in order from least to greatest in the Stem column. Write the leaves, the ones digits of the home runs, to the right of the corresponding stems. Step 3Order the leaves and write a key that explains how to read the stems and leaves.

Example 1 Display Data in a Stem-and-Leaf Plot Answer: A key shows how the digits are related. The ones digits of the data form the leaves. The tens digits of the data form the stems.

1.A 2.B 3.C 4.D Example 1 BUSINESS The table shows the number of hours spent aboard an airplane for a survey of business men and women. Make a stem-and-leaf plot of the data. A.B. C.D.

Example 2 Describe Data FITNESS The stem-and-leaf plot below shows the number of miles that Megan biked each day during July. Find the range, median, and mode of the data.

Example 2 Describe Data range:greatest distance – least distance = 30 – 5 or 25 miles median:average of middle two values, or 12 miles mode:most frequent value, or 10 miles Answer: range: 25 miles; median: 12 miles; mode: 10 miles

1.A 2.B 3.C 4.D Example 2 A.range: 25 inches; median: 10 inches; mode: 10 inches B.range: 10 inches; median: 25 inches; mode: 15 inches C.range: 25 inches; median: 14 inches; mode: 10 inches D.range: 23 inches; median: 12 inches; mode: 10 inches SNOWFALL The stem-and-leaf plot below shows the number of inches of snow that fell in Hightown during the month of January for the past 15 years. Find the range, median, and mode.

Example 3 Effect of Outliers ANIMALS The average life span of several animal species is shown in the stem-and-leaf plot. Which measure of central tendency is most affected by the inclusion of the outlier? The mode, 20, is not affected by the inclusion of the outlier, 40. Calculate the mean and median each without the outlier, 40. Then calculate them including the outlier and compare.

Example 3 Effect of Outliers

Example 3 Effect of Outliers Answer: So, the median is most affected by the inclusion of the outlier. The mean increased by 13.8 – 12.4, or 1.4, while the median increased by 15 – 13.5, or 1.5.

1.A 2.B 3.C 4.D Example 3 TEST SCORES The test scores earned by a class of middle school math students on a chapter test are shown. What measure of central tendency is most affected by the inclusion of the outlier? A.mean B.median C.mode D.mean and median

1.A 2.B 3.C 4.D Five Minute Check 3 REVIEW A.340.5; 358; 64 B.339.5; 358; 64 C.358; 339.5; 64 D.358; 340.5; 64 Find the median, mode, and range for the set of data. 321, 358, 344, 325, 374, 335, 365, 316, 369, 317, 345, 358, 330, 310

End of the Lesson

Resources Five-Minute Check (over Lesson 8–2) Image Bank Math Tools Line Plots

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