1. Lesson 11.1 Stem-and-Leaf Plots and Histograms
Essential Question: How do you make stem-and-leaf plots and histograms?

2. Before we start…
Group the prices according to the tens digit and complete the table.
The data below shows the prices of 14 brands of jeans. Write the data in numerical order.
25, 35, 29, 18, 20, 40, 26, 28, 33, 30, 39, 42, 38, 26
Tens Digit
Data 1 2 3 4

3. What is a stem-and-leaf plot?
A data display that organizes data based on their digits.
stem (the leading digit(s)) and a leaf (the last digit)
A key that tells you how to read the data.

4. How do you make a stem-and-leaf plot?
Separate the data into stem and leaves.
List the stems in numerical order.
Write the leaves in increasing order. Include a key to show what the stems and leaves represent.

5. Speeds of Animals The table lists the maximum running speeds of various animals. Display the speeds of the animals shown in a stem-and-leaf plot.
Animal
Speed (mi/h)
Elk 45
Cheetah 70
Greyhound 39
Wildebeest 50
Quarter horse 47
Zebra 40
Giraffe 32
Coyote 43

6. Baseball The number of homeruns hit by the 20 baseball players with the best single season batting averages in Major League Baseball since 1900 are listed below. Make a stem-and-leaf plot of the data.
14, 25, 8, 8, 7, 7, 19, 37, 39, 18, 42, 23, 4, 32, 14, 21, 3, 12, 19, 41

7. Test Scores The test scores for the students in a social studies class are listed below. Make stem-and-leaf plot of the scores.
92, 78, 73, 89, 98, 89, 83, 75, 83, 100, 69, 71, 96, 67, 81, 73, 88, 86, 82, 94

8. Track The distances (in centimeters) of 11 jumps from the final round of a women’s long jump competition are listed below. Make a stem-and-leaf plot to display the data.
669, 702, 644, 701, 684, 686, 676, 673, 688, 670, 662

9. Gymnastics The back-to-back stem-and-leaf plot shows the ages of members of the U.S. men’s and women’s 2004 Olympic gymnastics teams. Compare the ages of the gymnasts on the two teams.

10. How would you group this data
How would you group this data? How many data points fit in each group you’ve made?
The heights, in inches, of 15 players on a basketball team are listed below.
80, 65, 76, 83, 84, 79, 81, 80, 76, 81, 74, 80, 83, 79, 73

11. What is frequency? The number of data values in that interval.
A stem-and-leaf plot shows the frequencies of intervals determined by the stems.

12. What is a frequency table?
Is used to group data values into equal intervals, with no gaps between intervals and no intervals overlapping.

14. Science The numbers of named stars in a group of 34 constellations are listed below. Make a frequency table of the data. 7, 5, 4, 10, 5, 7, 2, 6, 8, 1, 5, 1, 3, 1, 12, 11, 2, 11, 2, 5, 0, 6, 14, 8, 3, 1, 15, 10, 0, 2, 0, 15, 9, 1

15. What is a histogram?
A bar graph that displays data from a frequency table.
Equal sized bars
Length = frequency
No space

16. How do you make a histogram?
Choose equal intervals that cover all of the data values.
Organize the data using a frequency table.
Use the intervals to draw the bars of the histogram.

17. Music Every Sunday morning, a radio station plays a countdown of the top 30 requested songs from the previous week. The table shows the number of weeks that each of the songs on this week’s top 30 have been on the countdown. Make a histogram of the data.

18. Typing Rates The numbers of words that students in a typing class can type in a minute are listed. Make a frequency table and histogram of the data. 25, 19, 23, 29, 34, 26, 30, 40, 33, 20, 35, 35, 25, 29, 36, 22, 31

19. School Lunches The number of students in your class who brought their lunch to school each day for the past two weeks is given below. Make a frequency table and histogram of the data. 21, 12, 15, 21, 11, 8, 16, 18, 23, 27, 12, 14, 12, 12

20. Traffic Patterns City officials are looking at traffic patterns at a major intersection. They have tracked the average number of cars backed up at the stoplight between 5 A.M. and 6:59 P.M.

21. Butterflies The histogram shows the butterflies spotted in a butterfly garden between 8 A.M. and 8 P.M.

22. How do you make stem-and-leaf plots and histograms?

23. Ticket Out the Door
The histogram shows a town population from 1881 to When was the population the greatest?