Consider a poll that reported that 44% of people from a certain region have tried marijuana. The survey polled 965
adults from the region and had a margin of error of plus or minus 4 percentage points with a 99% level of confidence.
Complete parts (a) through (c) below.
a. State the survey results in confidence interval form and interpret the interval.
The confidence interval of the survey results is (.).
(Round to two decimal places as needed.)
Interpret the interval. Choose the correct answer below.
OA. There is a 99% chance that the percentage of people in the region who have tried marijuana is within the
confidence interval.
B. We are 99% confident that the percentage of people in the region who have tried marijuana is within the
confidence interval.
OC. The confidence interval will contain the percentage of people in the region who have tried marijuana 99% of the
time.
OD. 99% of the 965 people from the region that were polled fell within the confidence interval.
b. If the polling company was to conduct 200 such surveys of 965 people from the region, how many of them would
result in confidence intervals that did not include the true population proportion?
Approximately of the confidence intervals would not include the true population proportion.
c. Suppose a student wrote this interpretation of the interval: "We are 99% confident that the percentage of people from
this region who have tried marijuana is within the confidence interval." What, if anything, is incorrect in
this internretation?
A) this interpretation is incorrect because the confidence interview is about a population not a sample
B) this interpretation is incorrect because the confidence level states the possibility that the sample proportion within the confidence interval
C) this interpretation is incorrect, because the confidence level represents how often the confidence interval contain the correct population proportion
D) there is nothing wrong with this interpretation