# Stem and Leaf Display

Pages: 7 (1678 words) Published: June 19, 2013
Stem and Leaf Plots Examples
1. A stem and leaf plot is a method used to organize statistical data. The greatest common place value of the data is used to form the stem. The next greatest common place value is used to form the leaves. 17 stem leaf

2. EXAMPLE: Make a stem and leaf plot of the algebra test scores given below. Then complete each question. 56, 65, 98, 82, 64, 71, 78, 77, 86, 95, 91, 59, 69, 70, 80, 92, 76, 82, 85, 91, 92, 99, 73 1st put the scores in numerical order.

56, 59, 64, 65, 69, 70, 71, 73, 76, 77, 78, 80, 82, 82, 85, 86, 91, 91, 92, 92, 95, 98, 99

Since the data range from 56 to 99, the stems range from 5 to 9. To plot the data, make a vertical list of the stems. Each number is assigned to the graph by pairing the units digit, or leaf, with the correct stem. The score 56 is plotted by placing the units digit, 6, to the right of stem 5.

Stem 5 6 7 8 9

Leaf 69 459 013678 02256 1122589

a. What type of graph does a stem and leaf plot represent when turned vertically? Histogram b. What was the lowest score on the algebra test? 56 c. What was the highest score on the algebra test? 99 d. In which interval did most students score? 90 to 99

Stem and Leaf Plots

Rev. 07.23.03

3. EXAMPLE: Make a stem and leaf plot of the history test scores given below. Then complete each question. 65, 82, 73, 91, 95, 86, 78, 69, 80, 88

1st put the scores in numerical order.

65, 69, 73, 78, 80, 82, 86, 88, 91, 95

Since the data range from 65 to 95, the stems range from 6 to 9. To plot the data, make a vertical list of the stems. Each number is assigned to the graph by pairing the units digit, or leaf, with the correct stem. The score 65 is plotted by placing the units digit, 5, to the right of stem 6.

Stem 6 7 8 9

Leaf 59 38 0268 15

a. What was the lowest score on the history test? 65 b. What was the highest score on the history test? 95 c. In which interval did most students score? 80 to 89 4. Data with more than two digits can be rounded to two digits before plotting or can be truncated to two digits. To truncate means to cut off. For a stem and leaf plot, you would truncate everything after the second digit. The number 355 would round to 36 The number 355 would truncate to 35 355 355 36 35

a. To what does 389 round? 39 b. To what does 389 truncate? 38

Stem and Leaf Plots

Rev. 07.23.03

5. A back-to-back stem and leaf plot is sometimes used to compare two sets of data or rounded and truncated values of the same data. In a back-to-back plot, the same stem is used for the leaves of both plots. 6. EXAMPLE: Estimated populations of counties in California are listed below. Make a back-to-back stem and leaf plot of the populations comparing rounded values and truncated values. County Butte Contra Costa Fresno Kern Marin Sacramento Put data into order. Then round and truncate to two digits. Pop. (thousands) 149 657 515 403 223 783 County San Bernardina San Francisco San Mateo Santa Barbara Santa Cruz Sonoma Pop (thousands) 893 679 588 299 188 300

Normal 149 188 223 299 300 403 515 588 657 679 783 893 Rounded 9 5 2 0 0 0 9 2 8 6 8 9

POPULATION IN THOUSANDS Rounded (2 digits) Truncated (2 digits) 15 14 19 18 22 22 30 29 30 30 40 40 52 51 59 58 66 65 68 67 78 78 89 89 Truncated 4 8 2 9 0 0 1 8 5 7 8 9 Using truncated data, 2|2 represents 220,000 – 229,999 people

Using rounded data, 2|2 represents 215,000 – 224,999 people

1 2 3 4 5 6 7 8

Stem and Leaf Plots

Rev. 07.23.03

7. EXAMPLE: The enrollments of several small colleges are listed below. Make a back-to-back stem and leaf plot of enrollments comparing rounded values and truncated values. Then answer each question College Miller Business School Capital College Para Professional Institute Parke College State Community Fashion Institute College of Art and Design Franklin...