In: Statistics and Probability
5. A shipment of 50 light bulbs contains 10 defective light bulbs. In order to test the quality of the shipment, a quality control engineer selects 5 light bulbs at random.
(a) How many different samples are possible?
(b) What is the probability the engineer will select exactly two
defective light bulbs?
(c) The shipment will be rejected if at least one of the light bulbs in the sample is defective. What is the probability the sample will be rejected?
in part b and c. plz, using another way to solve it. except for binomial distribution.
a) The total number of different samples possible here is
computed as:
= Number of ways to select 5 light bulbs from 50 light bulbs
Therefore there are 2118760 different samples possible here.
b) The probability that the engineer will select exactly two
defective light bulbs is computed here as:
= Number of ways to select 2 defective ones from 10 defective ones
* Number of ways to select 3 non defective ones from remaining 40
light bulbs / Total ways to select 5 bulbs from 50 bulbs
Therefore 0.2098 is the required probability here.
c) The probability that the shipment is rejected is computed here as:
= 1 - Probability that none of the 5 selected ones are defected
= 1 - (Number of ways to select 5 bulbs from 40 non defective ones) / Total ways to select 5 bulbs from 50 bulbs
Therefore 0.6894 is the required probability here.