1. Box-and-Whisker Plots

2. What does a box-and-whisker plot look like?
Whiskers
Get it?

3. How is a box-and-whisker plot set up?
You have four different sections. 4 1 2 3

4. Each section is worth 25% You have four different sections. 25% 25%

5. What percentages of the data are each of the sections?
1 1 AND AND , 2, AND 3 4 1 2 3

6. What does a box-and-whisker plot include?
Lower Quartile
Upper Quartile
Upper Extreme
Lower Extreme
Median

7. Our goal: To make a box-and-whisker plot of the following data:
8, 6, 3, 5, 3, 4, 2, 9

8. Always Always Always
Put the numbers in order from least to greatest.
8, 6, 3, 5, 3, 4, 2, 9
2, 3, 3, 4, 5, 6, 8, 9

9. Remember, we need 5 things:
Lower Extreme
Upper Extreme
Median
Lower Quartile
Upper Quartile

10. Let’s find those EXTREMES (Lower and Upper)
The lower extreme = the lowest number
The upper extreme = the highest number
(unless there is an outlier ^^)
Is there an outlier? no
2, 3, 3, 4, 5, 6, 8, 9

11. Extremes (continued)
What is the lower extreme? 2 What is the upper extreme? 9
2, 3, 3, 4, 5, 6, 8, 9

12. Now we have 2 out of 5 things that we need to know.
Lower Extreme Upper Extreme Median Lower Quartile Upper Quartile

13. Let’s find the median!
The median is the CENTER of the data
If there are two numbers, add together and divide by two (mean).
2, 3, 3, 4, 5, 6, 8, 9
4 + 5 2 9 2
4.5 = =

14. Now we have 3 out of 5 things that we need to know.
Lower Extreme Upper Extreme Median Lower Quartile Upper Quartile

15. Now we have to find the QUARTILES (Lower and Upper)
Lower Quartile – Median of the lower half
Upper Quartile – Median of the upper half
HOW DO WE SPLIT IT IN HALVES??
2, 3, 3, 4, 5, 6, 8, 9

16. How to split in halves:
2, 3, 3, 4, 5, 6, 8, 9
The lower half is LEFT of the median.
The upper half is RIGHT of the median.
Lower Half
Upper Half
Median

17. Finding the Lower Quartile:
2, 3, 3, 4, 5, 6, 8, 9
Median of the Lower Half
2, 3, 3, 4
3 + 3 2 6 2 3 = =

18. Finding the Upper Quartile:
2, 3, 3, 4, 5, 6, 8, 9 Median of the Upper Half 5, 6, 8, 9
6 + 8 2 14 2 7 = =

19. Now we have 5 out of 5 things that we need to know.
Lower Extreme Upper Extreme Median Lower Quartile Upper Quartile

20. What are they again?
Lower Extreme = 2 Upper Extreme = 9 Median = 4.5 Lower Quartile = 3 Upper Quartile = 7

21. How to we graph it?
Come up with your scales and intervals: The numbers only go from 2-9. What should our scale be? 1-10 What should our intervals be? 1

22. Draw the number line: 1 2 3 4 5 6 7 8 9 10

23. Plot your points
Lower Extreme = 2 Upper Extreme = 9 Median = 4.5 Lower Quartile = 3 Upper Quartile = 7 1 2 3 4 5 6 7 8 9 10

24. Draw a box around the quartiles:
Lower Extreme = 2 Upper Extreme = 9 Median = 4.5 Lower Quartile = 3 Upper Quartile = 7 1 2 3 4 5 6 7 8 9 10

25. Draw a line down the median:
Lower Extreme = 2 Upper Extreme = 9 Median = 4.5 Lower Quartile = 3 Upper Quartile = 7 1 2 3 4 5 6 7 8 9 10

26. We did it!!!!! Draw your whiskers:
Lower Extreme = 2 Upper Extreme = 9 Median = 4.5 Lower Quartile = 3 Upper Quartile = 7
We did it!!!!! 1 2 3 4 5 6 7 8 9 10

27. Thank you for downloading my Box and Whisker Plot Lesson!
HOPE YOU ENJOY!
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