# Binomial distribution.

• Apr 15th 2011, 08:39 AM
axz92
Binomial distribution.
Hey Guys, I need some more help here.

Im not sure how to solve this question:

It is known in the ice cream industry that 38% of people have chocolate as their favorite flavor ice cream.

Let X be the number of people in a sample of 10 who say chocolate is their favourite ice-cream flavor.

Calculate: P(X < 3)

Thanks.
• Apr 15th 2011, 08:49 AM
SpringFan25
P(X<3) = P(X=0) + P(X=1)+ P(X=2)

You should have been taught a method for finding the probabilities on the right hand side before being set the question. (binomial distribution, maybe?)
• Apr 15th 2011, 09:41 AM
axz92
no I wasn't given any method on how to solve this question, this is exactly the question given to me, so I myself am confused. Pls continue to guide me through this question.

Thanks alot
• Apr 15th 2011, 09:57 AM
Plato
Quote:

Originally Posted by axz92
It is known in the ice cream industry that 38% of people have chocolate as their favorite flavor ice cream. Let X be the number of people in a sample of 10 who say chocolate is their favorite ice-cream flavor. Calculate: P(X < 3)

This is simple binominal probability. We assume independence, the number of trials is N=10, the probability of success is p=0.38.
P(X=k)= Combin(N,k)p^k(1-p)^{N-k}, k=0,1,2. Add those up.

Note that the LaTeX compiler is down.
• Apr 15th 2011, 06:21 PM
axz92
How did u get the value 0,1,2 for the variable K?
• Apr 16th 2011, 12:10 AM
mr fantastic
Quote:

Originally Posted by axz92
How did u get the value 0,1,2 for the variable K?

*Ahem* ....
Quote:

Originally Posted by axz92
Hey Guys, I need some more help here.

[snip]

Calculate: P(X < 3)

Re:
Quote:

Originally Posted by axz92
no I wasn't given any method on how to solve this question, this is exactly the question given to me, so I myself am confused. Pls continue to guide me through this question.

Thanks alot

Then why would you be set this question to do?