1. Lesson 12-2 Pages 612-616 Measures of Variation

2. What you will learn! 1. How to find measures of variation. 2. How to use measures of variation to interpret and compare data.

3. Measures of variation Quartiles Lower quartile Upper quartile Interquartile range

4. Measures of Variation TermDefinition Range The difference between the least value and greatest value of the set. Median The value that separates the data set in half. Lower Quartile The median of the lower half of the set of data. Upper Quartile The median of the upper half of the set of data. Interquartile range The difference between the upper quartile and the lower quartile.

6. Example 1: Find the range of each set data. A.79,42,38,51,63,91 91 – 38 = 53

7. Example 1b: Find the range of each set data. 59 – 33 = 26 StemLeaf 3 3 3 5 7 7 8 4 0 3 3 4 9 5 4 9 4│3 = 43

8. Example 2: Find the interquartile range. 38,40,32,34,36,45,33 32333436384045 MedianLQUQ 40 – 33 = 7

9. Example 2b: Find the interquartile range. 2,27,17,14,14,22,15,32,24,25 Median 19.5 LQUQ 25 – 14 = 11 2141415172224252732

10. Example 3: The urban land in certain western and eastern states is listed below as the percent of each state’s total land. Western States Eastern States 1 1 1 1 1 0 0 0 3 2 2 2 1 1 1 0 3 3 4 5 6 6 8 5 4 4 0 8 9 9 9 9 9 9 1 1 3 3 4 4 5 2 3 6 7 3 5 1│3 = 13%4│0 = 4%

11. What is the median percent of urban land use for each region? Western States Eastern States 1 1 1 1 1 0 0 0 3 2 2 2 1 1 1 0 3 3 4 5 6 6 8 5 4 4 0 8 9 9 9 9 9 9 1 1 3 3 4 4 5 2 3 6 7 3 5 1│3 = 13%4│0 = 4% 1% 9%

12. Compare the range for each set of data. 1│3 = 13% Western States Eastern States 1 1 1 1 1 0 0 0 3 2 2 2 1 1 1 0 3 3 4 5 6 6 8 5 4 4 0 8 9 9 9 9 9 9 1 1 3 3 4 4 5 2 3 6 7 3 5 5% - 0% = 5% 35% - 3% = 32% 4│0 = 4%

13. Page 614 Guided Practice #’s 4-8

15. Pages 612-614 with someone at home and study examples! Read:

16. Homework: Pages 615-616 #’s 9-18, 23-33 Lesson Check 12-2

21. Page 753 Lesson 12-2