1. Outliers and Skewed Data

2. Warm Up Find the mean, median, mode and range of the following data:
3, 4, 5, 3, 5, 7, 9, 3, 8

3. Objective
The student will be able to identify outliers and how they affect data sets.

4. Exploration
Matapeake Middle School Basketball Team Spreadsheet.

5. Standard Deviation
Standard Deviation is a measure of how spread the set of numbers are in a data set.
Things needed to calculate standard deviation:
Mean
Variance
These are used to then calculate the standard deviation

6. With a Partner
Find the Outlier of the Data and Determine how it will Skew the Data:
1, 100, 2, 5, 3, 7, 3, 6, 10

7. Outliers and Skewed Data
Outliers are pieces of data that “don’t” fit within the data set.
They are either too large or too small.
Data has a shape to its graph and outliers can affect the shape of their graph.

8. Continued…

9. Continued

10. Continued…

11. Continued…

12. With a Partner:
Determine How the data is skewed:

13. Variance and Standard Deviation:
The average squared differences from the mean
Standard Deviation:
Is the square root of the Variance
Uses the lower case Greek letter Sigma:

14. Example

15. Continued… Find the Mean:
Calculate the difference between each height and the mean.

16. Continued

17. Continued…
Calculate Variance:

18. Continued…
Calculate the Standard Deviation: The square root of the Variance

19. With A partner… Find the standard deviation of the following:
2, 3, 4, 2, 4, 3, 4

20. Exit ticket and Homework
What does a negatively skewed graph look like?
Homework:
Worksheet.