Question

Perez Electronics buys monitors for its computers from another company. The monitors are received in shipments of 100 boxes, each containing 20 monitors. The quality assurance department at Perez Electronics first randomly selects one box from each shipment and then randomly selects 5 monitors from that box. The shipment is accepted if not more than 1 of 5 monitors is defective. The quality control inspector at Perez Electronics selected a box from a recently received shipment of monitors. Unknown to the inspector, this box contains 6 defective monitors.

a. What is the probability that this shipment will be accepted?

b. What is the probability that this shipment will not be accepted?

Answer 1

Answer:

Given,

Probability of defective = 6/20

p = 0.30

q = 1 - p

= 1 - 0.30

= 0.70

a)

To give the probability that this shipment will be accepted

Required probability = P(x = 0) + P(x = 1)

= 5C0*0.3^0*0.70^5 + 5C1*0.30^1*0.70^4

= 0.7^5 + 5*0.3*0.7^4

= 0.16807 + 0.36015

= 0.5282

Required probability = 0.5282

b)

To give the probability that this shipment will not be accepted

Required probability = 1 - P(Accepting the shipment)

substitute values

= 1 - 0.5282

= 0.4718

Required probability = 0.4718