1. Homework Questions

2. Quiz! Shhh…. Once you are finished you can work on the warm- up (grab a handout)!

3. Section 1.3 Numerical Summaries of Distributions (Quantitative)

4. Numerical Summaries A numerical summary of a distribution should report at least its center, and spread, or variability. A statistic is resistant if it is relatively unaffected by extreme observations.

5. The Mean

6. The Median Median (M) being the midpoint of the data set is a resistant measure of center. We just count to the middle value (averaging the two middle values if there is an even number within the data set). Example: 5 10 10 10 10 12 15 20 20 25 30 30 40 40 60 Example: 10 30 5 25 40 20 10 15 30 20 15 20 85 15 65 15 60 60 40 45

7. Comparing Mean & Median For a symmetric distribution, the mean and median are equal

8. Comparing Mean & Median For a distribution skewed to the right, the mean is to the right of the median

9. Comparing Mean & Median For a distribution skewed to the left, the mean is to the left of the median.

10. Interquartile Range

11. Find the IQR and the 5 Number Summary Five Number Summary – o Minimum, Q 1, Median, Q 3, Maximum 1, 3, 3, 4, 5, 6, 6, 7, 8, 8

12. Box Plot You can use the 5 Number Summary to create a box plot of the data.

13. Your turn… Find the 5 number summary, IQR, and create a box plot of the data 85, 91, 99, 101, 105, 109, 111, 119, 125

14. Outliers If an observation falls outside of 1.5 x IQR, then it is an outlier. For example, 85, 91, 99, 101, 105, 109, 111, 119, 125 IQR was _________ 1.5 x IQR = Do we have any outliers?

15. Homework Pg. 70 (80, 82-88, 90-96)