Question
A professional golfer is shopping for a new brand of golf ball. He likes most of the measures or one particular brand, but he wants to make sure that the brand has a desirable spin rate (the rate at which the ball spins on its axis after being struck by a golf club). He estimates that the ideal ball has a spin rate of about 7000 revolutions per minute for a five-iron shot. To test the spin rate of this new brand of ball, the golfer hits the brand of ball of 72 live-iron shots, and a computer measures the spin rate for each shot. The computer then produces the following histogram summarizing the 72 spin rates.
Explanation / Answer
based on above histogram
hence mean spin rate =476000/72 =6611
bin mid point(x) freq P(x) xP(X) 5000-5500 5250 5 26250 5500-6000 5750 10 57500 6000-6500 6250 14 87500 6500-7000 6750 20 135000 7000-7500 7250 17 123250 7500-8000 7750 6 46500 72 476000