1. Homework • Turn it in now. Has everyone turned in his/her assignment?

2. Answers to 1

3. Answers to 11

4. 2. 3. 76-84 4. 5. 5 6. 7. 10% 8. 9. 52.5% 10. 12. 13. 5 14. 15. 33 16. 17. 22% 18. 19. 30% Answers to the rest.

5. Grading • Write “graded by” and your name to that. • Count the number of items correct out of 20.

6. Histograms Statistics Mrs. Spitz Fall 2009

7. Objectives • Be able to construct a histogram given information in a problem. • Determine the ratio of 2 objects • Determine the percentage from a ratio.

8. Assignment • Pg. 529 #21-32

9. Definition • A bar graph that represents the data in a frequency distribution. The width of the bar represents each class, and the height of the bar corresponds to the frequency of the class.

10. Example 1 • A survey of 105 households is conducted and the number of kilowatt hours (kWh) of electricity that are used by each in a one-month period is recorded in the frequency distribution, shown in the figure. The histogram follows.

12. Number of Households Kilowatt Hours

13. Example 2 • The high temperatures at a ski resort during the 125-day ski season were recorded in a frequency distribution. The histogram for that is shown in the next slide. The temperature was between 15° and 20° on 15 days. • Use Figure 11.2 to find the number of days the temperature was 45° or above.

15. Example 4 • Use the histogram to find the number of days the temperature was 30° or below.

16. Example 4 • Use the histogram to find the number of days the temperature was 30° or below.

17. Strategy • Read the histogram • Add the frequencies for the classes of 10-15, 15-20, 20-25, and 25-30 Solution: 2 + 15 + 12 + 18 = 47 So, the number of days the temperature was 30° or below was 47.

18. Assignment Pg. 529 #21-32