Stem and Leaf Plots

Definitions- Range

Range- The difference between the greatest and least numbers in a data set

Data set: 23, 45, 60, 55, 80, 75, 15

Largest number: 80

Smallest number: 15

Difference: 80-15= 65

More on Range

Range is not a measure of central tendency.

It is a measure of variation…..it describes the spread of the data.

Stem and Leaf Plots

What is a stem and leaf plot? It is a way to represent specific data.

It organizes data so it can be analyzed visually and mathematically

When is it appropriate to use a stem and leaf plot?

When data can be grouped into intervals (stems) and the data values within the intervals can be plotted as the leaves.

Stem and Leaf Plots

Parts of stem and leaf plotsStemLeaf

Stem and Leaf Plots In a Stem and Leaf Plot, the data are

organized from least to greatest. The digits of the greatest place value usually form the Stems, the next place value of digits form the leaves.

Stem and Leaf Plots

How do we create them? We start with a data set All data should be in order from least

to greatest. Each stem and each leaf must be

represented. Always list the digit even if it is

repeated

Data set

Use the following data set to create a stem and leaf plot

19

6 7 10

11

13

18

25

21

12

5 12

20

21

11

12

Chick Weight (grams)

Stem and Leaf Plots

Step 1: Create the graph

Stem and Leaf Plots

Step 2: Choose the stems using digits in the tens place

19

6 7 10

11

13

18

25

21

12

5 12

20

21

11

12

What are the stems? (digits in the tens place)

0, 1, 2

The least value is 5, it has a 0 in the tens place

The greatest value is 25, it has a 2 in the tens place

Stem and Leaf Plots

Step 3: List the stems in order from least to greatest.

Stems: 0, 1, 2

0 12

Stem and Leaf Plots

Step 4: Order the leaves – least to greatest

19

6 7 10

11

13

18

25

21

12

5 12

20

21

11

12

0

1

2

5 6 7

0 1 1 2 2 2 3 8 9

0 1 1 5

Always write each leaf even if the data repeats

The tens digits form the stems

The ones digit

Forms the leavesAlways add a

Key: 1|2 = 12 g

Completing Graph

What do we always do before completing a graph?????????????

Making Inferences

When you analyze data, you can make inferences. That means, we can draw conclusions based on the data.

Making Inferences Find the mode ______ Find the range ______ Find the median _____

Stem Leaf

The stem and leaf plot shows the number of miles Jessie biked each day during the month of July.

0

1

2

3

5 5 6

0 0 0 0 1 2 2 5 8 8 9

1 2 5 8

0

Miles Jessie biked

2|1 = 21 miles

Analyzing Data

Stem Leaf

0

1

2

3

5 5 6

1 2 5 8

0

0 0 0 0 1 2 2 5 8 8 9

Miles Jessie biked

2|1 = 21 miles

What was the least number of miles Jessie biked in July? _______

What was the largest number of miles Jessie biked in July? _______

How many days did Jessie bike only 10 miles? ____

Making a stem and leaf plot

Use the data in the following table to create your own stem and leaf plot.

70 96 72 91

80 80 79 93

76 95 73 93

90 93 77 91

Quiz scores in Coach Bowen’s

Class

Make your own graph

Does it look like this?

Stem Leaf

7

8

9

0 2 3 6 7 9

0 0

0 1 1 3 3 3 5 6

Quiz scores in Coach Bowen’s Class

9|1= 91 on quiz

Answer the questions about your graph

What is the highest score on quiz? ____

What was the lowest score on quiz?____

What is the mode? ____ What is the median ____ What is the range of the quiz scores?

___

Question

Can we use stem and leaf plots to represent all data?

Conclusion: Stem and Leaf Plots

Are easy to read Are easy to create Great graph to display data Can not be used for all data sets