The Australian sheep dog is a breed renowned for its intelligence and work ethic. It is estimated that 40% of adult Australian sheep dogs weigh 65 pounds or more. A sample of 12 adult dogs is studied.
What is the probability that exactly 3 of them weigh 65 lb or more?
A) 0.0125
B) 0.1419
C) 0.8581
D) 0.9875

Question

Quizplus · Accepted Answer

The given problem follows a binomial distribution as the sample size is fixed and there are only two possible outcomes (weighs 65lb or more, or does not weigh 65lb or more) with a fixed probability for success (40%). 
Using the binomial probability formula, P(X = 3) = (12 choose 3) * (0.40)^3 * (0.60)^9 = 0.1419 (rounded to four decimal places). Therefore, the answer is B.

The Australian Sheep Dog Is a Breed Renowned for Its