A credit union took a random sample of 400 accounts and obtained the following 90% confidence interval for the mean checking account balance at the institution: $2185

Question

A credit union took a random sample of 400 accounts and obtained the following 90% confidence interval for the mean checking account balance at the institution: $2185 < μ(balance)< $3846.

Quizplus · Accepted Answer

The confidence interval obtained from the sample indicates that we are 90% confident that the true mean checking account balance at the credit union falls between $2185 and $3846. This statement correctly reflects the interpretation of a confidence interval. Option B is incorrect because we are making an inference about the population mean based on the sample, not about the sample mean itself. Option C is incorrect because it is not a correct interpretation of a confidence interval - we cannot make a claim about how many confidence intervals we would obtain from repeated sampling. Option D is incorrect because the confidence interval only applies to the credit union, not to the general population. Option E is incorrect because we are making an inference about the credit union, not about the entire country.

A Credit Union Took a Random Sample of 400 Accounts