Q8 A company that manufactures the Stinger tee claims that the thinner shaft and smaller head will lessen resistance and drag, reducing spin and allowing the ball to travel further. To test this claim they compared the distance travelled by golf balls hit off regular wooden tees to those hit with the Stinger tees. All the balls were struck by the same golf club using a robotic device set to swing the club head at approximately 95 mph. In the original experiment, 6 balls were used for each type of tee. If we want the margin of error in the estimate of the mean difference to be just 1.0 yard, with 95% level of confidence, how many balls should have been struck off each type of tee? Be conservative and set the standard deviation to 3.0 yards. 

(Hint: this is to determine sample size to estimate the difference in two population means)