Holt CA Course 1 7-3Choosing the Most Useful Measure Warm Up Warm Up Lesson Presentation California Standards Preview

Holt CA Course 1 7-3Choosing the Most Useful Measure Warm Up Find the mean, median, and mode of each data set. 1. 0, 2, 1, 7, 9, 2, , 18, 14, 16, 20, , 65, 125, 130, 470, California has 55 electoral votes. Other states in the west have 3, 4, 5, 7, and 11 electoral votes. Find the mean, median, and mode of the data set with and without California. mean: 3; median: 2; modes: 0, 2 mean: 19; median: 18; mode: 18 mean: 157.5; median: 112.5; mode: none with: mean: ≈14, median: 6, mode: none; without: mean: 6, median: 5, mode: none

Holt CA Course 1 7-3Choosing the Most Useful Measure SDAP1.4 Know why a specific measure of central tendency (mean, median) provides the most useful information in a given context. Also covered: SDAP1.1, SDAP1.3 California Standards

Holt CA Course 1 7-3Choosing the Most Useful Measure Recall that the mean and median describe the center of a data set. How do you decide which of these measures to use when describing a set of data? You should choose the measure that is most useful for the situation.

Holt CA Course 1 7-3Choosing the Most Useful Measure Additional Example 1: Describing a Data Set Step 1: Find the mean and median. The heights of players on a basketball team are 72, 86, 74, 73, and 75 inches. What are the mean and median? Is one measure more useful than the other for describing the typical height of a player on the team? Explain. Mean: 76 Step 2: Choose the most useful measure. Median: 74 The median is a more useful description of the typical player. There is only one player taller than the mean.

Holt CA Course 1 7-3Choosing the Most Useful Measure The measure that you use to a describe data set may depend on how the information is being used.

Holt CA Course 1 7-3Choosing the Most Useful Measure Additional Example 2: Using a Data Set to Persuade The number of hours Jordan spent studying for his last five exams are 4, 0.5, 3.5, 3, and 0.5. Should Jordan use the mean, median, or mode to convince his teacher that he spends enough time studying? Explain. Mean: 2.3 Median: 3 Mode: 0.5 Jordan should use the median because it makes the number of hours spent studying seem greatest.

Holt CA Course 1 7-3Choosing the Most Useful Measure Check It Out! Example 1 Step 1: Find the mean and median. The shoe size of players on a soccer team are 11, 10, 12, 11, and 16. What are the mean and median? Is one measure more useful than the other for describing the typical shoe size of a player on the team? Explain. Mean: 12 Step 2: Choose the most useful measure. Median: 11 The median is a more useful description of the typical player’s shoe size. The 16 shoe size is an outlier causing the mean to be higher.

Holt CA Course 1 7-3Choosing the Most Useful Measure Check It Out! Example 2 Elisa is shopping for skates and found the following prices: $35, $42, $75, $40, $47, $34, $45, and $40. Elisa wants to convince her parents to buy her skates. Should Elisa use the mean, median, or mode to describe the data set? Mean: $44.75 Mode: $40Median: $41 Elisa should use the measure that makes the price seem the lowest. She should use the mode.

Holt CA Course 1 7-3Choosing the Most Useful Measure Lesson Quiz 1. The top running speeds of six mammals are 15, 22, 30, 20, 26, and 37 miles per hour. What are the mean and median of this data set? Is one measure more useful than the other for describing the typical running speed of these mammals? Explain. 2. The price of a DVD at seven different stores is given below. Should Ann use the mean, median, or mode to convince a friend that the DVD is too expensive? Explain. $20, $12, $13, $17, $14, $12, $20 Mean: 25; median: 24; mean or median; there is no outlier. Mean; it makes the price seem highest.