Section 2.2, Part 2 Determining Normality

1. Section 2.2, Part 2Determining Normality AP Statistics

2. What is “Normal”? • Because we should only apply z-score to distributions that are normal, we need a process to determine whether a distribution is a normal distribution. AP Statistics, Section 2.2, Part 2

3. Symmetric? • The distribution should be roughly symmetric. • You can use a Boxplot to determine symmetry. AP Statistics, Section 2.2, Part 2

4. Are Walter Johnson’s Wins Normal? • 5, 14, 13, 25, 25, 33, 36, 28, 27, 25, 23, 23, 20, 8, 17, 15, 17, 23, 20, 15, 5 into list L1 • Run “1-Var Stats” • Is the data set symmetric? Where do you look? AP Statistics, Section 2.2, Part 2

5. Are Walter Johnson’s Wins Normal? • Look also at boxplot • Is the data set symmetric? AP Statistics, Section 2.2, Part 2

6. 68-95-99.7 Rule? • You can use the 68-95-99.7 rule with a histogram to see if the distribution roughly fits the rule. AP Statistics, Section 2.2, Part 2

7. Are Walter Johnson’s Wins Normal? • 5, 5, 8, 13, 14, 15, 15, 17, 17, 20, 20, 23, 23, 23, 25, 25, 25, 27, 28, 33, 36 AP Statistics, Section 2.2, Part 2

8. Are Walter Johnson’s Wins Normal? • Last step is the creation of the “normal probability plots • Let’s look at the book example: AP Statistics, Section 2.2, Part 2

9. Example 2.12 AP Statistics, Section 2.2, Part 2

10. Example 2.12 AP Statistics, Section 2.2, Part 2

11. Example 2.12 AP Statistics, Section 2.2, Part 2

12. Somewhat normal (somewhat linear) AP Statistics, Section 2.2, Part 2

13. Example 2.12 AP Statistics, Section 2.2, Part 2

14. Example 2.12 AP Statistics, Section 2.2, Part 2

15. Example 2.12 AP Statistics, Section 2.2, Part 2

16. Not normal (not linear) AP Statistics, Section 2.2, Part 2

17. Walter Johnston Normal? AP Statistics, Section 2.2, Part 2

18. Assignment • Exercises 2.26 – 2.31, 2.33, 2.36 to finish Section 2.2 • Exercises 2.39, 2.40, 2.42, 2.45, 2.47 to finish Chapter 2 AP Statistics, Section 2.2, Part 2