1. Stem-and-Leaf Plot
Lowest value is 67 and highest value is 125, so list stems from 6 to 12.
Stem
Leaf
6 |
7 |
8 |
9 |
10 |
11 |
12 | 6 2
Divide each data value into a stem and a leaf. The leaf is the rightmost significant digit. The stem consists of the digits to the left. The data shown represent the first line of the ‘minutes on phone’ data used earlier. The complete stem and leaf will be shown on the next slide. 2 8 3
To see complete display, go to next slide. 4

2. Stem-and-Leaf Plot Key: 6 | 7 means 67 6 | 7 7 | 1 8 8 | 2 5 6 7 7
6 | 7
7 | 1 8
8 |
9 |
10 |
11 | 2 6 8
12 | 2 4 5
Key: 6 | 7 means 67
Stress the importance of using a key to explain the plot. 6|7 could mean 6700 or .067 for a different problem. A stem and leaf should not be used with data when values are very different such as 3, 34,900, 24 etc. The stem-and leaf has the advantage over a histogram of retaining the original values.

3. Stem-and-Leaf with two lines per stem
Key: 6 | 7 means 67
6 | 7
7 | 1
7 | 8
8 | 2
8 |
9 | 2
9 |
10 |
10 |
11 | 2
11 | 6 8
12 | 2 4
12 | 5
1st line digits
2nd line digits
With two lines per stem the data is more finely “chopped”. Class width is 5 times the leaf unit. All stems except possibly the first and last must have two lines even if one is blank. For this data set, the first line for the stem 6 can be blank because there are no data values from 60 to 64.
1st line digits
2nd line digits

4. Dot Plot
Phone 66 76 86 96
106
116
126
minutes
Dot plots also allow you to retain original values.

5. NASA budget (billions of $) divided among 3 categories.
Pie Chart
Used to describe parts of a whole
Central Angle for each segment
NASA budget (billions of $) divided among 3 categories.
Pie charts help visualize the relative proportion of each category. Find the relative frequency for each category and multiply it by 360 degrees to find the central angle.
Billions of $
Human Space Flight
Technology
Mission Support
Construct a pie chart for the data.

6. Pie Chart Human Space Flight 5.7 143 Technology 5.9 149
Billions of $
Degrees
Human Space Flight
5.7
143
Technology
5.9
149
Mission Support
2.7 68
14.3
360
Total
Mission
Support
19%
Human
Space Flight
40%
NASA Budget
(Billions of $)
Technology
41%

7. Scatter Plot Absences Grade x 8 2 5 12 15 9 6 y 78 92 90 58 43 74 81
Final
grade
(y) 40 45 50 55 60 65 70 75 80 85 90 95 2 4 6 8 10 12 14 16
Absences (x)