1. Lesson 5-8 Pages 238-242 Measures of Central Tendency Lesson Check 5-7

2. What you will learn! 1.How to find the mean, median, and mode as measures of central tendency. 2.How to use the mean, median, and mode.

3. Measures of central tendency Mean Median Mode

4. What you really need to know! When working with numerical data, it is often helpful to use one or more numbers to represent the whole set. These numbers are called measures of central tendency.

5. StatisticDefinition Mean sum of the data divided by the number of items in the set Median middle number of the ordered set Mode number or numbers that occur most often What you really need to know!

7. Example 1: The revenue of the 10 highest grossing movies as of June 2000 are given in the table. Find the mean, median, and mode of the revenues. Top 10 Movie Revenues (millions of $) 601330 461313 431309 400306 357290

8. Example 1: Mean601 330 461 313 431 309 400 306 357 +290 3,798 3,798 ÷ 10 379.8 $379.8 million

9. 290306309313330357400431461601 Example 1: Median 330 + 357 = 687 687 ÷ 2 = 343.5 $343.5 million330357

10. Example 1: Mode No Mode This is no number or numbers that appear more than any other number. Therefore there is no mode. 290306309313330357400431461601

11. Example 2: The line plot on the next screen shows the number of gold medals earned by each country that participated in the 1998 Winter Olympic Games in Nagano, Japan. Find the Mean, median, and mode for the gold medals won.

12. Example 2: 78910345601211121314 x x x x x x x x x xx x x x x x x x x x x xxx There are 24 numbers in this set of data!

13. Example 2: 78910345601211121314 x x x x x x x x x xx x x x x x x x x x x xxx 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 1 + 1 + 2 + 2 + 2 + 2 +3 + 3 + 5 + 5 + 6 + 6 + 9 + 10 + 12 = 69

14. Example 2: 78910345601211121314 x x x x x x x x x xx x x x x x x x x x x xxx 69 ÷ 24 = 2.875 mean

15. Example 2: 78910345601211121314 x x x x x x x x x xx x x x x x x x x x x xxx The numbers are all ready in order. Since there are 24 numbers, the median would be 12 from the top and bottom of the line plot. The median is 2.

16. Example 2: 78910345601211121314 x x x x x x x x x xx x x x x x x x x x x xxx The mode is 0

17. Example 3: The quiz scores for a math class are 8, 7, 6, 10, 8, 8, 9, 8, 7, 9, 8, 0, and 10. Identify an extreme value and describe how it affects the mean.

18. Example 3: 0 is an extreme value. Mean with 0 is 7.5 Mean without 0 is 8.2 The 0 lowers the mean by 0.7 points. 0677888889910

19. Example 4: The table shows the monthly salaries of the employees at two bookstores. Find the mean, median, and mode for each set of data. Based on the averages, which bookstore pays its employees better?

20. Bob’s Books The Reading Place 12901400 14001450 14001550 16001600 36502000 9340 ÷ 5 8000 ÷ 5 $1868$1600 Median Mode

21. Bob’s Books The Reading Place Mean$1,868$1,600 Median$1,400$1,550 Mode$1,400 No Mode The Reading Place pays its employees better.

22. Example 5: Jenny’s bowling average is 146. Today she bowled 138, 140, and 145. What does she need to score on her fourth game to maintain her average?

23. Example 5: 146 4 = 584 138 + 140 + 145 = 423 584 – 423 = 161 Jenny needs to score at least 161 on her fourth game.

24. Page 241 Guided Practice #’s 3-9

26. Pages 238-240 with someone at home and study examples! Read:

27. Homework: Pages 241-242 #’s 10-16 all #’s 21-35 Lesson Check 5-8

31. Page 735 Lesson 5-8

32. Lesson Check 5-8