Question 9: (from chapter 5) A stunt person injures himself an average of three times a year. Use Poisson probability formula to calculate the probability that he will be injured: a. 4 times a year b. less than twice this year. c. more than three times this year. d. once in the six months. Question 10: (from chapter 6) An industrial sewing machine uses ball bearings that are targeted to have a diameter of 0.75 inch. The lower and upper specication limits under which the ball bearings can operate are 0.74 and 0.76 inch, respectively. Past exercise has indicated that the actual diameter of the ball bearings is approximately normally distributed, with the mean and the standard deviation shown in the table below: Results from the past exercise: Actual diameter of the ball bearings: 0,758 inch Actual standard deviation of the ball bearings: 0,004 inch What is the probability that a ball bearing is: a. between the target and the actual mean? b. between the lower specication limit and the target? c. above the upper specication limit? d. below the lower specification limit? e. Of all the ball bearings, 93% of the diameters are greater than what value