Question

An industrial sewing machine uses ball bearing that are targeted to have a diameter of 0.74 inch. The lower and upper specification limits under which the ball bearings can operate are 0.72 inch and 0.76 inch, respectively. Past experience has indicated that the actual diameter of the ball bearings is approximately normally distributed, with a mean of 0.745 inch and a standard deviation of 0.009 inch. Complete parts a through e below.

a. What is the probability that a ball bearing is between the target and the actual mean?

Round to four decimals.

b. What is the probability that a ball bearing is between the lower specification limit and the target?

c. What is the probability that a ball bearing is above the upper specification limit?

d. What is the probability that a ball bearing is below the lower specification limit?

e. Of all the ball bearings, 94% of the diameters are greater than what value?

Answer 1