Question

Suppose we are interested in determining the average amount of money students spend on textbooks every year. If we obtained 420 simple random samples and constructed a 90% confidence interval for each sample, we would expect ______ of the confidence intervals to contain the true population mean.

Answer 1

Given that, sample size (n) = 420 and we constructed 90% confidence interval for the population mean for each sample.

Then 420 * 0.90 = 378 of the confidence intervals contain the true population mean.

OR 90% of the confidence intervals contain the true population mean.

Therefore, Suppose we are interested in determining the average amount of money students spend on textbooks every year. If we obtained 420 simple random samples and constructed a 90% confidence interval for each sample, we would expect 378 (or 90%) of the confidence intervals to contain the true population mean.