EXAMPLE 2 Finding Median, Mode, and Range Find the median, mode(s), and range of the numbers below SOLUTION Write the numbers in order from least to greatest Median:Because there is an even number of data values, the median is the mean of the two middle values. Median = = = 60.5

EXAMPLE 2 Range: Find the difference between the greatest and the least values. Range = 65 – 38 = 27 Mode: The number that occurs most often is 64. Finding Median, Mode, and Range

EXAMPLE 3 Choosing the Best Average Dance-a-Thon: You receive the pledge amounts listed below for your participation in a dance-a-thon. Which average best represents the pledge amounts? $1 $8 $12 $10 $45 $9 $1 $7 $6 The mean suggests that most pledges are greater than they actually are. = $ Find the mean: STEP 1 SOLUTION

EXAMPLE 3 STEP 2 Find the median: The median is $ 8. It is the middle value of the nine values. STEP 3 Find the mode: The pledge that occurs most often is $ 1. The mode suggests that most pledges are less than they actually are. The median best represents the pledge amounts. ANSWER Choosing the Best Average

EXAMPLE 3 STEP 4 Find the range: $45 – $1 = $44 The range suggests that the data are more evenly spaced than they are. The median best represents the pledge amounts. ANSWER Choosing the Best Average

EXAMPLE 4 Standardized Test Practice SOLUTION Mean = = 20 = 21 To find the mean cost of the trees, divide the sum of the costs by the total number of trees purchased. ANSWER The mean cost of the trees is $21. The correct answer is B.

GUIDED PRACTICE for Examples 2, 3, and 4 Find the median, mode(s), and range. 3. 9, 13, 19, 14, 16, 11, 7, 6, 13 ANSWER 13; 13; , 52, 23, 79, 66, 17, 20, 10 ANSWER 21.5; no mode ; 69

GUIDED PRACTICE In Example 3, you receive three more pledges of $15, $20, and $22. Which measure best represents the pledge amounts? ANSWERmedian for Examples 2, 3, and 4 What If? 5.

GUIDED PRACTICE 6. What are the mode and median costs of the trees in Example 4 ? ANSWER 20; 20 for Examples 2, 3, and 4