A confidence interval is defined as:
A) a point estimate plus or minus a specific level of confidence.
B) a lower and upper confidence limit associated with a specific level of confidence.
C) an interval that has a 95% probability of containing the population parameter.
D) a lower and upper confidence limit that has a 95% probability of containing the population parameter.

Question

Quizplus · Accepted Answer

A confidence interval is an estimation of an unknown parameter of a population, based on a sample from that population, which includes both a lower and upper limit, such that the true parameter value lies within the range of the interval with a specified level of confidence. Therefore, the best choice is B, which defines a confidence interval as a lower and upper confidence limit associated with a specific level of confidence. Choice A is incorrect since a confidence interval consists of a range of values rather than a single point estimate. Choice C is incorrect because it refers to the probability of the interval containing the population parameter, which is a common misinterpretation of confidence intervals. Choice D is incorrect because it conflates the true probability of the population parameter being within the interval with the confidence level of the interval.

A Confidence Interval Is Defined As