Question

A researcher is interested in finding a 90% confidence interval for the mean number minutes students are concentrating on their professor during a one hour statistics lecture. The study included 102 students who averaged 34.1 minutes concentrating on their professor during the hour lecture. The standard deviation was 12.5 minutes. Round answers to 3 decimal places where possible.

a. To compute the confidence interval use a ? t z  distribution.

b. With 90% confidence the population mean minutes of concentration is between  and   minutes.

c. If many groups of 102 randomly selected members are studied, then a different confidence interval would be produced from each group. About  percent of these confidence intervals will contain the true population mean minutes of concentration and about  percent will not contain the true population mean minutes of concentration.

Answer 1