To test whether consuming alcohol impairs driving ability, the DMV conducted the following experiment. Seven volunteers were asked to drive through an obstacle course prior to consuming any alcohol and again after drinking two drinks. Driving ability was measured by recording the total reaction time (in seconds) of a driver in avoiding the various obstacles on the course. The data are given below. At the 3% level of significance, is it true that consumption of two drinks impairs driving ability. Assume differences between reaction times before and after are normally distributed. Driver #1 #2 #3 #4 #5 #6 #7
Reaction time without akchal (Before) 8.82 6.62 9.84 10.81 9.20 11.67 4.42
Reation tme with alcohol (Ater) 1 10.61 8.18 12.24 13.45 8.88 10.88
Difference (After- Before) 5.38 1.79 1.56 2.4 2.64 -0.32 0.96

Required:
a. State the null and alternative hypotheses.
b. Calculate the sample mean and standard deviation of difference in reaction time.