A study compared flu vaccine administered by injection and flu vaccine administered as a nasal spray. Each of 4,000 children under the age of 5 who participated in the study received both a nasal spray and an injection, but only one was the real vaccine and the other was salt water. At the end of the flu season, it was determined that of the 2,000 children receiving the real vaccine by nasal spray, 10.1% got the flu. Of the 2,000 children receiving the real vaccine by injection, 15.6% got the flu. The 95% confidence interval for the difference in treatment proportions is:
A) 0.00±0/021
B) 0.055±0.017
C) 0.055±0.024
D) 0.055±0.021
E) 0.00±0.023

Question

A study compared flu vaccine administered by injection and flu vaccine administered as a nasal spray. Each of 4,000 children under the age of 5 who participated in the study received both a nasal spray and an injection, but only one was the real vaccine and the other was salt water. At the end of the flu season, it was determined that of the 2,000 children receiving the real vaccine by nasal spray, 10.1% got the flu. Of the 2,000 children receiving the real vaccine by injection, 15.6% got the flu. The 95% confidence interval for the difference in treatment proportions is: ​
A) 0.00±0/021
B) 0.055±0.017
C) 0.055±0.024
D) 0.055±0.021
E) 0.00±0.023

Quizplus · Accepted Answer

The correct choice is D) 0.055±0.021. This is because the difference in the proportion of children who got the flu between the nasal spray group (10.1%) and the injection group (15.6%) is 5.5% or 0.055. The confidence interval provided in option D accurately reflects this difference and the margin of error around it, indicating the statistical precision of the estimate.

A Study Compared Flu Vaccine Administered by Injection and Flu