1. Histograms
EQ: What conclusions can be drawn from a histogram? What can a histogram tell you about the spread of a data set?
BOP
DWP - Mr. Adams had 24 guests at his house for a party. Each guest brought one item.
• One-third of the guests brought drinks.
• One-fourth of the guests brought a dessert.
• The rest of the guests brought chips.
How many guests brought chips?

2. DWP - Mr. Adams had 24 guests at his house for a party
DWP - Mr. Adams had 24 guests at his house for a party. Each guest brought one item.
• One-third of the guests brought drinks.
• One-fourth of the guests brought a dessert.
• The rest of the guests brought chips.
How many guests brought chips?

3. Concept/Vocabulary Word
Definition
Cluster
a group of things or persons close together
Distribution
The arrangement of values in a data set
Frequency Table
A list of items or intervals that shows the number of times, or frequency, with which they occur.
Gap
a break or opening
Histogram
A display that shows the distribution of numeric data. The range of data values, divided into intervals, is displayed on the horizontal axis. The vertical axis shows frequency.
interval
is a set of real numbers with the property that any number that lies between two numbers in the set is also included in the set
Peak
being at the point of maximum frequency, intensity, use, etc.

4. A bar graph can be used to display and compare data
A bar graph can be used to display and compare data. The scale of a bar graph should include all the data values and be easily divided into equal intervals.
Hundreds of different languages are spoken around the world. The graph shows the numbers of native speakers of four languages.

5. PUT THESE STEPS IN YOUR STUDY GUIDE!
A histogram is a bar graph that shows the frequency of data within equal intervals. There is no space between the bars in a histogram.
Follow these steps to make a histogram:
Step 1: Make a frequency table of the data. Be sure to use equal intervals.
Step 2: Choose an appropriate scale and interval for the vertical axis. The greatest value on the scale should be at least as great as the greatest frequency.
Step 3: Draw a bar graph for each interval. The height of the bar is the frequency for that interval. Bars must touch but not overlap.
Step 4: Label the axes and give the graph a title.
PUT THESE STEPS IN YOUR STUDY GUIDE!

6. Example 3: Making a Histogram
Course 2
1-4
Bar Graphs and Histograms
Example 3: Making a Histogram
The table below shows the number of hours students watch TV in one week. Make a histogram of the data.
Step 1: Make a frequency table of the data. Be sure to use equal intervals.
6 ///
7 //// ////
8 ///
9 ////
1 //
2 ////
3 //// ////
4 //// /
5 //// ///
Number of Hours of TV
Frequency
Number of Hours of TV
1–3 15
4–6 17
7–9 17

7. 1-4 Bar Graphs and Histograms
Course 2
1-4
Bar Graphs and Histograms
Example 3 Continued
Step 2: Choose an appropriate scale and interval for the vertical axis. The greatest value on the scale should be at least as great as the greatest frequency. 20 16 12 8 4
1–3
Frequency
Number of Hours of TV 15
4–6 17
7–9

8. 1-4 Bar Graphs and Histograms
Course 2
1-4
Bar Graphs and Histograms
Example 3 Continued
Step 3: Draw a bar graph for each interval. The height of the bar is the frequency for that interval. Bars must touch but not overlap. 20 16 12 8 4
1–3
Frequency
Number of Hours of TV 15
4–6 17
7–9

9. 1-4 Bar Graphs and Histograms
Course 2
1-4
Bar Graphs and Histograms
Additional Example 3 Continued
Step 4: Label the axes and give the graph a title.
Hours of Television Watched 20 16 12 8 4
1–3
Frequency
Number of Hours of TV 15
4–6 17
7–9
Frequency
1–3
4–6
7–9
Hours

10. PUT FINAL GRAPH IN YOUR STUDY GUIDE!
Construct A Histogram
Mrs. Pittman gave her class a history test. The
class of 16 students had the following scores:
75, 80, 65, 80, 95, 85, 65, 80,
90, 80, 70, 85, 90, 70, 85, 70
Follow the steps to create a histogram.
PUT FINAL GRAPH IN YOUR STUDY GUIDE!

11. Grade range Frequency 60-69 70-79 80-89 90-99
Step 1 - Make a Frequency Table
Grade range
Frequency
60-69
70-79
80-89
90-99
Step 2: Choose an appropriate scale and interval for the vertical axis. The greatest value on the scale should be at least as great as the greatest frequency.

12. Step 3: Draw a bar graph for each interval
Step 3: Draw a bar graph for each interval. The height of the bar is the frequency for that interval. Bars must touch but not overlap.
Step 4: Label the axes and give the graph a title.

13. The graph below shows the results of a
survey of 390 families.
How many of the families in the
survey have more than three children?
A. 120
B. 130
C. 140
D. 260

14. The graph below shows the results of a survey of 390 families.

15. CC Investigation Grade Six Page 53 #13-15
Holt Course 2 Lesson 1-4 Practice
Allow students to work in pairs to complete Problem 5.2 Part B.
Have students put frequency tables and histograms on poster paper. Hang them in the class to compare and contrast. We are looking for groups that used different intervals to talk about similarities and differences between the histograms. When having this discussion, be sure to talk about the distribution of the data as well as if students have gaps in their histograms what that may represent and where they think the data clusters and peaks are.
Have them go back and fill in or make any adjustments to their vocabulary list.

16. On a separate sheet of paper, construct frequency tables and histograms for
the following problems. Turn in for a class work grade.
CC Investigations
Basketball Tournament
The table shows the winning scores in the first round
of the basketball tournament. 90 69 70 89 62 97 64 68 79 67 77 66 65 99 82
100 81 78 53 80 86 73 72 52

17. What are the greatest and least winning scores?
Divide the range of the data into equal intervals that
will be represented by bars on the histogram.
Give the range for each interval.
Explain why you chose that number of intervals.
Make a table to show the frequency of scores in
each interval.
5. Make a histogram of the data. Draw a bar for each
interval to represent the frequency.
6. Summarize what the histogram show about the
data.

18. 2. Ages of mall shoppers 23 33 21 18 17 45 40 12 31 27 29 24 19 25 36 38 20
3. Class grades on a history exam 97 84 93 76 87
100 92 90 70 85 83 99 89 91 96 74 73 80
See page 48 in CC Investigations for sample histograms.

19. 4. Weights of pumpkins in lbs.5 16 23 8 7 9 12 15 20 18 6 21 11 10 14 24 17

20. Interval Frequency 51-60 2 61-70 11 71-80 10 81-90 6 91-100 3
Answers for basketball tournament
100; 51
51-60, 61-70, 71-80, 81-90,
Five intervals divides the data into enough groups without
making a histogram that is too large. 4.
Interval
Frequency
51-60 2
61-70 11
71-80 10
81-90 6
91-100 3

21. EXIT TICKET What are the SIMILARITIES and DIFFERENCES between bar
graphs and
histograms?

22. Correct all problems on geometry handouts
EXIT TICKET: What are the SIMILARITIES and DIFFERENCES between bar graphs and histograms?
Homework:
Correct all problems on geometry handouts
completed in class last week. It was checked on
Friday for a class work grade.
Make all corrections on a separate sheet of paper.
Staple corrections to the top of the original papers.
All corrections are due on Wednesday.

23. Complete workbook page 4
Did you note this information in your chart?
The difference is that a bar graph represents individual pieces of data where the histogram represents
intervals of data.
The bar graph usually has spaces between the bars where the histogram has the bars adjacent to each other.
Both should have a title, the labels for the axes, and scale for the axes.
Complete workbook page 4