Stem and Leaf Plots

1. Stem and Leaf Plots

2. 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 The Range

3. More on Range • Range is not a measure of central tendency. • It is a measure of variation…..it describes the spreadof the data.

4. 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.

5. Stem and Leaf Plots Parts of stem and leaf plots Stem Leaf Stem Leaf This is the leaf This is the stem

6. 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. 56 Leaf Stem

7. 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

8. Data set Chick Weight (grams) • Use the following data set to create a stem and leaf plot

9. Stem and Leaf Plots • Step 1: Create the graph Stem Leaf

10. Stem and Leaf Plots • Step 2: Choose the stems using digits in the tens place 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

11. Stem and Leaf Plots • Step 3: List the stems in order from least to greatest. Stems: 0, 1, 2 Stem Leaf 0 12

12. Stem and Leaf Plots • Step 4: Order the leaves – least to greatest Stem Leaf 0 1 2 5 6 7 0 1 1 2 2 2 3 8 9 0 1 1 5 The tens digits form the stems Always write each leaf even if the data repeats Always add a Key: 1|2 = 12 g The ones digit Forms the leaves

13. Completing Graph • What do we always do before completing a graph????????????? Add a title!!!!

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

15. Making Inferences 10 Miles Jessie biked • Find the mode ______ • Find the range ______ • Find the median _____ 25 Stem Leaf 12 0 1 2 3 5 5 6 0 0 0 0 1 2 2 5 8 8 9 1 2 5 8 The stem and leaf plot shows the number of miles Jessie biked each day during the month of July. 0 2|1 = 21 miles

16. Analyzing Data 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? ____ Miles Jessie biked 2|1 = 21 miles Stem Leaf 5 0 1 2 3 5 5 6 0 0 0 0 1 2 2 5 8 8 9 30 1 2 5 8 0 4

17. Make your own graph Making a stem and leaf plot • Use the data in the following table to create your own stem and leaf plot. Quiz scores in Coach Bowen’s Class

18. Does it look like this? Quiz scores in Coach Bowen’s Class Stem Leaf 7 8 9 0 2 3 6 7 9 0 0 0 1 1 3 3 3 5 6 9|1= 91 on quiz

19. 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? ___ 96 70 93 85 26

20. Question • Can we use stem and leaf plots to represent all data? No

21. 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