Question

A new vaccine was tested to see if it could prevent the ear infections that many infants suffer from. Babies about a year old were randomly divided into two groups. One group received vaccinations, and the other did not. The following year, only 334 of 2458 vaccinated children had ear infections, compared to 501 of 2451 unvaccinated children. Complete parts a) through c) below. a) Are the conditions for inference satisfied? O A. No. It was not a random sample. B. Yes. The data were generated by a randomized experiment, less than 10% of the population was sampled, the groups were independent, and there were more than 10 successes and failures in each group. O C. No. The groups were not independent. OD. No. More than 10% of the population was sampled. b) Let p, be the sample proportion of success in the unvaccinated group, and let pbe the sample proportion of success in the vaccinated group. Find the 95% confidence interval for the difference in rates of ear infection, P1 - P22 The confidence interval is %,%). (Do not round until the final answer. Then round to one decimal place as needed.)

Answer 1

The statistic software output for this problem is:

The 95% confidence interval is :

(4.8% , 8.9%)