SOLUTION: Hello, this is the problem Im having currently, I have no idea were to start. Problem: Of 30 microwave ovens 6 are defective. what is the probability that exactly 2 of the fi

Algebra ->  Probability-and-statistics -> SOLUTION: Hello, this is the problem Im having currently, I have no idea were to start. Problem: Of 30 microwave ovens 6 are defective. what is the probability that exactly 2 of the fi      Log On


   

Question 311203: Hello,
this is the problem Im having currently, I have no idea were to start.
Problem: Of 30 microwave ovens 6 are defective. what is the probability that exactly 2 of the first 4 microwave ovens are defective?
Thanks so much!
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
the expected probability of a defective oven is 6/30 or .2

the 2 out of 4 is a binomial probability
___ Pd (defective) is .2 while Pn (not defective) is .8

probability of 2 out of 4 defective is the 3rd term of the expansion of the binomial ___ (Pd + Pn)^4 ___ 4C2(Pd^2 * Pn^2)

6(.2^2 * .8^2) = .1536