Which is true about a 98% confidence interval for a population proportion based on a given sample?
I. We are 98% confident that other sample proportions will be in our interval. II. There is a 98% chance that our interval contains the population proportion. III. The interval is wider than a 95% confidence interval would be.
A) None
B) III only
C) I and II
D) II only
E) I only

Question

Quizplus · Accepted Answer

III is correct because increasing the confidence level from 95% to 98% requires widening the interval to capture the population proportion with higher certainty. Statements I and II reflect common misconceptions; confidence intervals provide a range for the population parameter, not the probability of sample statistics falling within that range or the chance of the interval containing the parameter.

Which Is True About a 98% Confidence Interval for a Population