Lesson 2-4 Pages 69-72

1. Lesson 2-4 Pages 69-72 Mean, Median, and Mode Lesson Check 2-3

2. What you will learn! How to find the mean, median, and mode of a set of data.

3. Vocabulary

4. What you really need to know! • The meanis the sum of the data divided by the number of data items. • The medianis the middle number of the ordered data, or the mean of the middle two numbers.

5. What you really need to know! • The modeis the number (or numbers) that occur most often. • The mean, median, and mode are each measures of central tendency.

7. Find the mean, median, and mode for each set of data! 1, 5, 9, 1, 2, 6, 8, 2 Mean = 4.25 Median = 3.5 Mode = 1 and 2

8. Find the mean, median, and mode for each set of data! 82, 79, 93, 91, 95, 95, 81 Mean = 88 Median = 91 Mode = 95

9. Example 2: The line plot shows the number of children of U. S. presidents. Would the mean, median, or mode best represent the number of children?

10. There are 46 numbers. Add them together and divide the sum by 46. 0 1 2 3 4 5 6 7 8 9 10 11 x x x 7 x 6 6 x x 5 x x x x 4 x x x x x 3 x x x x x x 2 x x x x x x x 1 1 x x x x x x x x x x x x x x x x x x

11. 143 ÷ 46  3.1 (mean) 0 1 2 3 4 5 6 7 8 9 10 22 x x x x 0 x x 24 30 x x x x 5 x x x x x 12 x x x x 18 x x x x x x x x x 14 x x x x x x x x 8 10 x x x x x x x x x x

12. Since there are 46 numbers, the middle would be the 23rd number from the each end of the list. That would be a 2 and a 3. Take the mean of these two numbers to get the median. 0 1 2 3 4 5 6 7 8 9 10 x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

13. 5 ÷ 2 = 2.5 (median) 0 1 2 3 4 5 6 7 8 9 10 x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

14. Mean = 3.1 Median = 2.5 Mode = 2 11 7 6 6 5 4 3 2 1 1 0 1 2 3 4 5 6 7 8 9 10 x x Median of 2.5 best represents the data! x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

15. Extra: When the numbers are all in the same neighborhood, the MEAN is the way to go! If there is one number out of the neighborhood, then the MEDIAN is the choice!

16. Page 71 Guided Practice #’s 4-9

18. Read: Pages 69-71 with someone at home and study examples!

19. Homework: Page 72 #’s 10-16 #’s 20-27 Lesson Check 2-4

22. Page 568 Lesson 2-4

23. Lesson Check 2-4

24. Mid-Chapter Practice Test Page 74 #’s 1-15

32. Example 1: The table below shows the number of species of animals found at 30 major zoos across the U.S. Find the mean.

33. There are 30 numbers. Add them together and divide the sum by 30. 436.46 13,094 ÷ 30 Calculator

34. Example 2: The table below shows the number of gold medals won by each country participating in the 2002 Winter Olympic games. Find the mean, median, and mode of the data.

35. There are 25 numbers. Add them together and divide the sum by 25. 79 ÷ 25 = 3.16

36. Example 2: The table below shows the number of gold medals won by each country participating in the 2002 Winter Olympic games. Find the mean, median, and mode of the data.

38. Order the numbers from greatest to least. Find the number or numbers in the middle of the list. The median for this data is 2.

39. The mode is the number or numbers that occur most often. The mode for this data is 0.