Americans typically take off 5 sick days each year, with a standard deviation of 2 days. A researcher would like to know whether psychiatrists take off less sick days than the average American. The researcher obtains a sample of 16 psychiatrists who, on average, take 3 days of sick leave a year. Test this researcher s hypothesis using an alpha level of .01. Given the scenario below, what is the critical value?

(which one?)

-2.33

-1.96

-1.64

+1.96