In a box containing 60 bulbs, 6 are defective. What is the probability that out of a sample of 5 bulbs

(i) none is defective


(ii) exactly 2 are defective


(i) Using Bernoulli’s Trial P(Success=x) = nCx.px.q(n-x)


x=0, 1, 2, ………n and q = (1-p), n =5


The probability of success, i.e. the bulb is defective = p =


q =


probability of that no bulb is defective piece=


P(0 defective items) =


5C0.()0()5


(5


(ii) Using Bernoulli’s Trial P(Success=x) = nCx.px.q(n-x)


x=0, 1, 2, ………n and q = (1-p), n =5


The probability of success, i.e. the bulb is defective = p =


q =


probability of that there are exactly 2 defective pieces=


P(2 defective items) =


5C2.()2()3


(


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