Let the following sample of 8 observations be drawn from anormal population with unknown mean and standard deviation: 21, 14,13, 24, 17, 22, 25, 12. [You may find it useful to reference the ttable.]
a. Calculate the sample mean and the sample standard deviation.(Round intermediate calculations to at least 4 decimal places.Round "Sample mean" to 3 decimal places and "Sample standarddeviation" to 2 decimal places.)
b. Construct the 90% confidence interval for the populationmean. (Round "t" value to 3 decimal places and final answers to 2decimal places.)
c. Construct the 95% confidence interval for the populationmean. (Round "t" value to 3 decimal places and final answers to 2decimal places.)
d. What happens to the margin of error as the confidence levelincreases from 90% to 95%?
As the confidence level increases, the margin of error becomeslarger.
As the confidence level increases, the margin of error becomessmaller.
