1. Histograms

2. What is a histogram? A histogram is a type of bar graph whose bars represent the frequencies of NUMERIC DATA within intervals. Y-Axis has the frequency X-Axis has the intervals

3. Intervals You need to look at your data and decide your intervals. This is similar to a stem-and-leaf plot because of the intervals. Example: Amy lists her quiz scores. This is her list: 88, 95, 75, 72, 95, 96, 85, 83, 84, 80, 70, 92 What intervals would you chose?

4. Stem-and-Leaf Plot Example: Amy lists her quiz scores. This is her list: 88, 95, 75, 82, 95, 96, 85, 83, 84, 80, 70, 92 The intervals could be 70-79, 80-89, and 90-99. The stem-and-leaf plot would look like this: StemsLeaves 789789 0 5 0 2 3 4 5 8 3 5 5 6

5. Frequency Tables Once you have your intervals decided, make a frequency table. Frequency – the amount of times it occurs Example: Amy lists her quiz scores. This is her list: 88, 95, 75, 82, 95, 96, 85, 83, 84, 80, 70, 92 IntervalsFrequency 70-79 80-89 90-99

6. Creating a histogram! IntervalsFrequency 70-792 80-896 90-994 Title: Frequency Label: Intervals: What observations can you make about the distribution of the data?

7. Stem-and Leaf Plot vs. Histogram How are they similar? How are they different? StemsLeaves 789789 0 5 0 2 3 4 5 8 3 5 5 6 Title: Amy’s Quiz Scores Frequency Label: Quiz Grades Intervals: 70-79 80-89 90-99 65432106543210

8. Things to remember: You will use NUMERIC DATA. You decide intervals based on the data. It does not always have to be in tens. Must be constructed from a frequency table. All bars must touch and be the same width. X-Axis has intervals and a label. Y-Axis has frequencies. You need to have a title.

9. Your turn! Students were surveyed and asked how many hours they play outside each week. They said: 6, 9, 4, 5, 0, 7, 1, 5, 4, 8, 3, 2, 2, 3, 2, 4, 9, 4, 0, Title: Frequency Label: IntervalsFrequency Intervals:

10. How did you do? Students were surveyed and asked how many hours they play outside each week. They said: 6, 9, 4, 5, 5, 7, 1, 5, 4, 8, 3, 2, 2, 3, 2, 4, 9, 4, 0, 8 Title: Playing Outside Frequency Label: Hours Outside IntervalsFrequency 0-12 2-35 4-57 6-72 8-94 Intervals: 0-1 2-3 4-5 6-7 8-9 12 10 8 6 4 2 0

11. Histograms What observations can you make about the distribution of the data in your histogram? How can a histogram be helpful to you? What things do you need to watch out for when making a histogram?

12. Percent Bar Graph

13. What is a percent bar graph? A percent bar graph is a type of bar graph where you graph relative frequencies to help you visualize how the data is distributed for CATEGORICAL DATA. Y-Axis has the Relative Frequency (%) X-Axis has the categories

14. Make a Table Example: Sue asked her 25 classmates what their favorite color was. 4 people said green, 6 people said purple, 5 people said pink, 7 people said blue, and 3 people said yellow. Favorite Colors ColorGreenPurplePinkBlueYellow Frequency

15. Relative Frequency Table To make a percent bar graph, you need to know the relative frequency of each category. Relative Frequency – the ratio of the frequency to the total as a fraction or percent Favorite Colors ColorGreenPurplePinkBlueYellow Frequency46573 Relative Frequency 4 ---- = ---- 25 100 6 ---- = ---- 25 100 5 ---- = ---- 25 100 7 ---- = ---- 25 100 3 ---- = ---- 25 100

16. Creating a percent bar graph! Title: Favorite Colors Relative Frequency (%) Categories: Green Purple Pink Blue Yellow What observations can you make about the data? Color Gree n PurplePinkBlueYellow Frequ ency 46573 %1624202812 30 25 20 15 10 5 0 Label: Color

17. Creating a percent bar graph! Title: Favorite Colors Relative Frequency (%) Categories: Green Purple Pink Blue Yellow What observations can you make about the data? Color Gree n PurplePinkBlueYellow Frequ ency 46573 %1624202812 30 25 20 15 10 5 0 Label: Color

18. Things to remember: You will use CATEGORICAL DATA. You need to make a relative frequency table. The percentage is the frequency out of the whole. You need to get to 100%. All bars must touch and be the same width. X-Axis has categories and a label. Y-Axis has relative frequencies (percents). You need to have a title.

19. Your turn! Title: Relative Frequency (%) Categories: What observations can you make about the data? ElectiveArtBandOrchestraTheatre Frequen cy 1018148 % 0 Label: When I went to lunch, I asked people what their elective was. Their answers are in the table.

20. How did you do? Title: Elective Classes Relative Frequency (%) Categories: Art Band Orchestra Theatre What observations can you make about the data? ElectiveArtBandOrchestraTheatre Frequen cy 1018148 %20362816 Label: Elective Class When I went to lunch, I asked people what their elective was. Their answers are in the table. 40 30 20 10 0

21. Percent Bar Graph What observations can you make about the data in your percent bar graph? How can a percent bar graph be helpful to you? What things do you need to watch out for when making a percent bar graph?

22. Compare How are histograms and percent bar graphs similar? How are histograms and percent bar graphs different? How do you know which kind of graph to use?