1. Texas Algebra I Unit 3: Probability/Statistics
Lesson 27: Stem and Leaf Plots

2. Lesson Objectives: TEKS
The student will be able to:
Define Stem and Leaf Plot and identify key components
Interpret data given in a stem and leaf plot
Organize a given data set into a stem and leaf plot
Use a stem and leaf plot to identify/calculate mode, median, and range.

3. Stem and Leaf plot- A stem and leaf diagram provides a visual summary of your data. This diagram provides a partial sorting of the data and allows you to detect key information quickly.
leaf
stem 3 4
0 1 5 6 2 7
key 3 2
= 32
Must have a key in order to interpret data properly!!

4. Analysis of data leaf stem 3 0 0 1 2 4 0 1 5 6 9 9 6 2 7 1 4 5 9 key 3 4
0 1 5 6 2 7
key 3 2
= 32
This data set has 14 entries:
30, 30, 31,32, 40, 41, 56, 59, 59, 62, 71, 74, 75, 79

5. Analysis of data leaf stem 3 0 0 1 2 4 0 1 5 6 9 9 6 2 7 1 4 5 9 key 3 4
0 1 5 6 2 7
key 3 2
= 32
Purpose of plot is to make it simple to find 3 of 4 of the measures of central tendency. Look at plot to find:
Mode: 30, 59
Median: average 56 and 59→ 57.5
Range: = 49

6. Analysis of data: another example9 2 3 5 7 8 5
= 0.5
Find the mode, median, and range of this set.

7. Putting given set in plot
Draw your table
Decide on stem’s place value (write key)
Place numbers in table
Re-order if necessary
Here is the data set: {25, 45, 89, 45, 42, 23, 74, 45, 28, 52, 36, 38, 69, 23}

8. Lesson Objectives: TEKS
The student will be able to:
Define Stem and Leaf Plot and identify key components
Interpret data given in a stem and leaf plot
Organize a given data set into a stem and leaf plot
Use a stem and leaf plot to identify/calculate mode, median, and range.