Jane Researcher is studying the percentage of ethanol in DWI arrestees' blood. She tests 16 subjects and finds a mean of 1.8% with a standard deviation of .2%.
a.) Calculate the z score for a subject with an ethanol percentage of 2.0%
b.) What is the (estimated) standard error of the mean?
c.) Produce a 95% confidence interval for the true mean percentage of ethanol in DWI arrestees.