A company that manufactures rivets used by commercial aircraft manufacturers knows that the shearing strength of (force required to break) its rivets is of major concern. They believe the shearing strength of their rivets is normally distributed, with a mean of 925 pounds and a standard deviation of i8 pounds.
a. If they are correct, what percentage of their rivets has a shearing strength greater than 900 pounds?
b. What is the upper bound for the shearing strength of the weakest 1% of the rivets?
c. If one rivet is randomly selected from all of the rivets, what is the probability that it will require a force of at least 920 pounds to break it?
d. Using the probability found in part c, what is the probability, rounded to the nearest tenth, that 3 rivets in a random sample of i0 will break at a force less than 920 pounds?