Question

Suppose that the probability of a defective part is .02. Suppose that you have a shipment of 200 parts. What is the probability that 5 or fewer parts will be defective?

please explain how to do this in excel and by hand as if i was just learning this.

Answer 1

Please don't hesitate to give a "thumbs up" in case you're satisfied with the answer

So, this involves calculating the probability using binomial distribution.

p(Defect) = .02

n = 200

The above parameters of binomial distribution are given below.

Why are we using binomial distribution? Because the outcome of this event is either a Success ( defect) , or a Failure ( not defect).

So, P(X<=5)

= BINOM.DIST(5, 200, 0.02, 1) [Excel formula calculates this, the function takes the parameters given in the formula]

= 0,7867

So, the probability that 5 or fewer parts are defective is .7867