Estimating the Difference between Two Population Proportions Answers

Check the conditions for constructing a confidence interval for the difference in proportions. Random condition: 10% condition: Large Counts condition: Are all the conditions for inference met?

✔ does not applymetnot met

does not apply✔ metnot met

✔ YesNoNot enough information

Check the conditions for constructing a confidence interval for the difference in proportions. Random condition: 10% condition: Large Counts condition: Are all the conditions for inference met?

met✔ not metdoes not apply

met✔ not metdoes not apply

Yes✔ NoNot enough information

A well-known coffee shop wants to estimate the difference in the proportion of caffeinated-coffee customers who order a large drink as compared with decaf-coffee customers who order a large. In a random sample of 500 caffeinated-coffee customers, 37% ordered larges. In a random sample of 370 decaf-coffee customers, 27% ordered larges. Based on the 90% confidence interval (0.048, 0.152), is there convincing evidence of a difference between the population proportions of caffeinated customers who order larges versus decaf customers who order larges? . Because contained in the interval, there is to believe there a difference in the proportions of caffeinated customers who order larges versus decaf customers who order larges.

✔ 00.320.90

is✔ is notmay be

✔ convincing evidencenot enough evidenceplausible evidence

Researchers want to test a new hand exercise plan for arthritis patients to see if they have improved flexibility. They recruited 110 patients with arthritis in their hands and randomly assigned them to one of two treatment groups: group 1 took their regular medicine and did the new hand exercises; and group 2 only took medicine. After one month, 42 of the 55 in group 1 improved in their flexibility, and 37 of the 55 in group 2 improved their flexibility. Based on the 95% confidence interval (–0.076, 0.258), is there convincing evidence of a difference in the proportion of patients like these who would show improvement in flexibility if they did the new hand exercises along with taking the medicine versus just taking the medicine? Because contained in the interval, there is to believe there a difference in the proportion of patients like these who would show improvement in flexibility if they did the new hand exercises along with taking the medicine versus just taking the medicine.

✔ isis not

convincing evidence✔ not enough evidence

✔ is is not

A bank wants to estimate the difference in the proportion of its "big" customers who have a second account with a different bank and the proportion of its "small" customers who also have an account with another bank. Of the 200 “big” customers who were randomly selected, 160 claimed to also bank with other banks. Of the 300 “small” customers who were randomly selected, 120 claimed to also bank with other banks.

is✔ is not

not enough evidence✔ convincing evidence

✔ is is not