A golf pro wants to determine if Titleist Pro V1 golf balls (1) travel farther, on average, than Callaway Chrome Soft golf balls (2). A robot hits 9 of each ball, selected at random, and the distance traveled is measured. Assume the distances traveled are normally distributed. The average distance traveled by the 9 Titleist Pro V1 golf balls is 261.1 yards with standard deviation 10 yards, and the average distance traveled by the 9 Callaway Chrome Soft golf balls is 249.3 yards with standard deviation 12 yards. Which test should the golf pro use to determine if Titleist Pro V1 golf balls travel a longer average distance than Callaway Chrome Soft golf balls?
a. pairedt test for means
b. paredz test for means
c. Ottest for proportions
d. test for means
e. test for means
f. Ottest for proportions