# Math Help - Binomial distribution.

1. ## Binomial distribution.

1. The probability that a randomly chosen sales prospect (a buyer) will buy insurance is 0.2. If an insurance salesman calls on six prospects, what is the probability that:

i. He will make exactly for four sales.
He will make more than four sales.

where do i go from here

f

2. Originally Posted by math321
1. The probability that a randomly chosen sales prospect (a buyer) will buy insurance is 0.2. If an insurance salesman calls on six prospects, what is the probability that:

i. He will make exactly for four sales.
He will make more than four sales.

where do i go from here

f

This is a binomial distribution with
$p=.2,n=6$

Binomial distribution - Wikipedia, the free encyclopedia

for the first part you want k=4.

For the 2nd part the sum of the probabilties of 5 sales and 6 sales

3. is there a particular formula to work with

4. Originally Posted by math321
is there a particular formula to work with
Did you go to the link? It is right there? look for the probability mass function.

5. i got

6!
-----
4! (2!)

6. Originally Posted by math321
i got

6!
-----
4! (2!)
Your answer is greater than 1. How can it possibly be correct?! You have clearly not used the formula correctly, part of it is missing. Go to your textbook or class notes and review examples.