A manufacturing company uses an acceptance scheme on production items before they are shipped. The plan is a two-stage one. Boxes of 25 are readied for shipment and a sample of 3 is tested for defectives. If any defectives are found, the entire box is sent back, for 100 percent screening. If no defectives are found, the box is shipped.
Q: Now suppose the manufacturing company decides to change its acceptance scheme. Under this new scheme an inspector takes one at random, inspects it, and then replaces it in the box; a second inspector does likewise. Fianlly a third inspector goes through the same procedure. The box will not be shipped if any of the three find a defective.
ANSWER THE FOLLOWING. AND PLEASE EXPLAIN IN WORDS HOW TO SOLVE THIS PROBELM
a) What is the probability that a box containing 3 defectives will be shipped?
b) What is the probability that a box containing only 1 defective will be sent back for screening?