1. AP Statistics Section 13.2 A

4. Example: A random digit dialing sample of 2092 adults found that 1318 used the Internet. Of the users, 1041 said they expected businesses to have Web sites that give product information 294 of the nonusers said this.   a) Construct a 95% confidence interval for the proportion of all adults who use the Internet (calculations only)

5. Example: A random digit dialing sample of 2092 adults found that 1318 used the Internet. Of the users, 1041 said they expected businesses to have Web sites that give product information; 294 of the nonusers said this.   b) Construct and interpret a 95% confidence interval to compare the proportion of users and nonusers who expect businesses to have websites. Full inference toolbox.

6. Hypothesis: Conditions:

7. Calculations: Interpretation:

8. The researchers in the study selected two separate samples from the two populations they wanted to compare. Many comparative studies start with just 1 sample, then divide it into 2 groups based on data gathered from the subjects. The two-proportion z procedures of this section are valid in such situations. This is an important fact about these methods.