1. Histograms & Stem-Leaf Plots
Kinda like bar graphs but just a lil’ different.

2. Stem and Leaf plot
Keelan, a pro athlete, scores every time he steps on the court. His points per game throughout the season are listed below:
4, 5, 8, 13, 17, 17, 19, 20, 20, 21, 24, 28, 31, 32, 35
The “stem” is the tens place, the “leaf” is the ones place.
Stem
Leaf
4, 5, 8 1
3, 7, 7, 9 2
0, 0, 1, 4, 8 3
1, 2, 5

3. Stem and Leaf plot What was the student’s lowest grade?
List of student grades. Make a stem and leaf plot.
Stem
Leaf 5 8 6
6, 8 7
2, 7, 7
5, 8, 9 9
1, 1, 5
What was the student’s lowest grade?
What was the student’s highest grade?
How many failing grades does the student have?

4. Team A: 65, 42, 56, 49, 58, 42, 61, 55, 45, 72
Team B: 57, 60, 48, 49, 52, 61, 58, 37, 63, 48
Team A
Team B 3 7 4
8 8 9
8 6 5 5
2 7 8
5 1 6
0 1 3 2
Football State
Championship Scores
The tens digits are the stems.
The ones digits are the leaves.
Put Team A’s scores on the left side and Team B’s scores on the right.
Title the graph and add a key.
Key: |4|8 means 48
2|4| means 42

5. Theme Park Attendance by Age
People
0-5 78
6-10 97
11-15
155
16-20
198
21-25
189
26-30
123
31-35 80
36-40 58
41-45 31
51-55 15
56-60 12
61-65 8
66-70 5
70+ 2

6. Theme Park Attendance by Age
This data is Skewed.
It has a tendency towards one side.
In this case, it is positive skewed (leaning left)
Negative skew leans right.

7. Characteristics of Frequency Tables and Histograms
Range of values split evenly.(Ex: goes up by 5 each time 1-5,
6-10…)
Histograms:
Like a bar graph.
The bars are touching.

8. Frequency of landing heads after 20 coin flips
0-2
3-5 1
6-8 5
9-11 8
12-14 4
15-17 2
18-20

9. Frequency of landing heads after 20 coin flips
This data is distributed normally. A Normal distribution.
Normal distribution is centered

10. Number of Customers in a Restaurant During the Day
Time
# of Customers
11:00-12:00 15
12:00-1:00 35
1:00-2:00 51
2:00-3:00 36
3:00-4:00 13
4:00-5:00
5:00-6:00 24
6:00-7:00 37
7:00-8:00 57
8:00-9:00 31
9:00-10:00 18
10:00-11:00 6

11. Number of Customers in a Restaurant During the Day
This is a bimodal distribution.
It has two peaks.

12. ON YOUR OWN PAPER

13. How to make Frequency Tables
The numbers of students enrolled in Western Civilization classes at a university are given below. Use the data to make a frequency table with intervals.
12, 22, 18, 9, 25, 31, 28, 19, 22, 27, 32, 14
Step 1: Identify the least and greatest values.
The least value is 9. The greatest value is 32.

14. How to make Frequency Tables
Step 2: Divide the data into equal intervals.
For this data set, use an interval of 10.
Enrollment in Western
Civilization Classes
Step 3 List the intervals in the first column of the table. Count the number of data values in each interval and list the count in the last column. Give the table a title.
Number Enrolled
Frequency
1 – 10 1
11 – 20 4
21 – 30 5
31 – 40 2

15. How to make a Histogram
A histogram is a bar graph used to display the frequency of data divided into equal intervals. The bars must be of equal width and should touch, but not overlap.

16. How to make a Histogram
Use the frequency table in Example 2 to make a histogram.
Step 1: Use the scale and interval from the frequency table.
Enrollment in Western
Civilization Classes
Number Enrolled
Frequency
1 – 10 1
11 – 20 4
21 – 30 5
31 – 40 2
Step 2: Draw a bar for the number of classes in each interval.
All bars should be the same width. The bars should touch, but not overlap.

17. Pick a number between 1-50 Create a frequency Table Stem Leaf 1 2 3 41 2 3 4 5
Create a frequency Table
Number
Frequency
0-9
10-19
20-29
30-39
40-50

18. Making a Histogram from a frequency Table

19. Pennies
Year
Age
2017
2012 5
2007 10
2002 15
1997 20
1992 25
1987 30
1982 35
1977 40
1972 45
1967 50
Make a list of the ages of your pennies.
Create a stem and leaf plot of the ages.
Create a frequency table of the ages.
Create a histogram of the ages.