1. Section 12.2 Comparing Two Proportions
AP Statistics

2. Our inferential work so far…
Has been about the distribution of sample means
and the distribution of the difference of sample means.
and the distribution of sample proportions

3. The sampling distribution of the difference of proportions

4. The shape of the sampling distribution of difference of proportions
If these conditions are met, the sampling distribution of difference of proportions is approximately normal

5. Two proportion confidence interval

6. Example
A study investigated the effect of pre-school on use of social services.
What is the 95% confidence interval?
Population
Description
Sample size
Sample proportion 1
Control 61
.803 2
Preschool 62
.613

7. Calculate the Confidence Interval
1: Populations & Parameter of Interest
3: Calculations
2: Procedure Name & Conditions
4: Interpret

8. 1: Population, Parameter of Interest, H0 and Ha
3: Calculations
2: Procedure Name & Conditions
4: Interpret

9. 1: Population, Parameter of Interest, H0 and Ha
3: Calculations
2: Procedure Name & Conditions
4: Interpret

10. Assignment Section 12.3: 12.23-12.33 odd
Chapter Review: odd