Jean Researcher is studying the percentage of ethanol in DWI arrestees's blood. She tests 16 subjects and finds a mean 1.8% with a standard deviation of .2%
a) Calculate the z score for the 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.