The mean drying time of paint in a certain application is 12 min. A new additive is tested to see if it reduces the drying time. One hundred specimens are painted. and the sample mean drying time 33 recorded. Assume that the population standard deviation of drying time is 2 min. Let a be the mean drying time for the new paint. The null hypothesis H0 : ,u 2 12 is tested against the alternative H1 : ,u.