Inspectional

what is the probability that a building inspector?

If 6 of 18 new buildings in a city violate the building code, what is the probability that a building inspector, who randomly selects 4 of the new buildings for inspection, will catch (a) none of the buildings that violate the building code; (b) 1 of the new buildings that violate the building code; (c) 2 of the new buildings that violate the building code; (d) at least 3 of the new buildings that violate the building code? PLEASE HELP ME!

Public Comments

1. This is a BINOMIAL DISTRIBUTION problem. The probability of exactly x successes is n trials is: P(X=x)=b(x;n,p) = (nCx)(p^x)((1-p)^(n-x)) where nCx is number of combinations of n things taken x at a time, and "^" means exponentiation. n = 4 p = 6/18 = .3333 For x = 0,P(X=0) = (4C0)(0.3333^0)(0.6667^4) = 0.1976 xp(X=x) 00.197570373 10.395081479 20.29627 30.098740742 40.012340741 At least 3 means 3 or 4: 0.098740742 + 0.012340741 = .1108