1. Chapter 18 Sampling Distribution

2. Key Concepts

3. Example 1 Suppose that about 13% of the population is left handed. A 200 seat school auditorium has been built with 15 lefty seats. In a class of 90 students what is the probability that there will not be enough seats for the left handed students?

4. Plan We want the probability of finding more that 16.7% left handed students out of a sample size of 90 students if the proportion of lefties is 13%.

5. Always check conditions Randomization Condition: 10% condition: Success/ Failure np>10 nq > 10

6. State the parameter and the sampling distribution model p= The conditions are satisfied N( mean ( use population proportion), SD) N(.13,.035)

7. Draw it

8. Find the z-score z= P( p >.167) =

9. Example 2 Information on a packet of seeds claims that the germination rate is 92%. What is the probability that more than 95% of the 160 seeds in the packet will germinate?

10. Plan

11. Conditions

12. State the parameter and the sampling distribution model p= The conditions are satisfied N( mean ( use population proportion), SD) N( )

13. Plot it

14. z score