Section 1.2 Part 2

1. Section 1.2Part 2 AP Statistics September 11, 2008 Berkley High School, D1B1

2. Describing with Numbers: Spread/Standard Deviation • s2 is called the variance, and its in units2 • s is called the standard deviation, and its in units. AP Statistics, Section 1.2, Part 2

3. Describing with Numbers: Spread/Standard Deviation • s measures spread about the mean and should be used only when the mean is chosen as the measure of center • s equals 0 only when there is no spread. This happens only when all observations have the same value. • s is not resistant. Outliers effect it adversely. AP Statistics, Section 1.2, Part 2

4. Calculating s by hand AP Statistics, Section 1.2, Part 2

5. Calculating s by hand AP Statistics, Section 1.2, Part 2

6. Calculating s by hand AP Statistics, Section 1.2, Part 2

7. Calculating s by hand AP Statistics, Section 1.2, Part 2

8. Calculating s using TI-83 AP Statistics, Section 1.2, Part 2

9. Calculating s using TI-83 AP Statistics, Section 1.2, Part 2

10. Calculating s using TI-83 AP Statistics, Section 1.2, Part 2

11. Linear Transformations • Adding “a” does not change the shape or spread • Adding “a” does change the center by “a” AP Statistics, Section 1.2, Part 2

12. Linear Transformations • Multiplying by “b” does change the shape or spread by “b” • Multiplying by “b” does change the center by “b” AP Statistics, Section 1.2, Part 2

13. Assignment • Exercises 1.40 – 1.47, The Practice of Statistics. AP Statistics, Section 1.2, Part 2