Pharmaceutical scientists tested the effectiveness of a new drug designed to cure malaria. They randomly assigned 400 infected lab rats to receive either the new drug or an existing drug and recorded how many
rats were cured at the end of the study. Here are their results:
Cured
Not
Total
New drug
176
24
200
Existing drug
168
32
200
They want to use these results to construct a 99% confidence interval to estimate the difference in the
proportion of these rats that would be cured under each drug (new - existing). Assume that all of the
conditions for inference have been met.
Which of the following is a correct 99% confidence interval based on their data?