# Can someone please help me with a Statistics problem? Need help finding the probabilities?

File is attached with the problem

### 1 Answer

Relevance

- PuzzlingLv 73 years agoFavorite Answer
Use the binomial probability formula:

P(X = k) = C(n,k) * p^k * q^(n-k)

n : number of trials (11)

k : number of "successes" (2 bad grapefruit)

p : probability of "success" (0.19)

q : probability of "failure" (1-p = 0.81)

I think you can just plug that in and get the answer you need:

P(X = 2) = C(11,2) * 0.19^2 * 0.81^9

As for part B, you should consider the opposite case. Figure out the probability of getting 0 bad grapefruit or 1 bad grapefruit and subtract from 1.

P(X ≥ 2) = 1 - P(X < 2)

= 1 - (P(X = 0) + P(X = 1))

You have the formula for P(X = k), so just plug in k=0 and k=1, then subtract that from 1.

P(X = 0) = C(11,0) * 0.19^0 * 0.81^11

P(X = 1) = C(11,1) * 0.19^1 * 0.81^10

P(X ≥ 2) = 1 - (P(X = 0) + P(X = 1))

- Login to reply the answers

Still have questions? Get your answers by asking now.