# Can some one explain hwo to find probability?

• March 17th 2011, 10:18 AM
Nafiro100
Can some one explain hwo to find probability?
A salesperson has to sell a minimum of 50 cars to earn the sales bonus. To date this month he/she has sold 46 cars. Today the salesperson has appointments with 10 prospective customers. He estimates that he/she has a 55% chance of success with each customer.
What is the probability that he/she will earn his/her bonus today?
• March 17th 2011, 11:35 AM
Sambit
This is a Binomial distribution with probability of success p=0.55, n=10; you need to obtain probability of getting 4.
• March 17th 2011, 11:43 AM
Plato
Quote:

Originally Posted by Sambit
This is a Binomial distribution with probability of success p=0.55, n=10; you need to obtain probability of getting 4.

It should be at least four.
• March 18th 2011, 08:58 AM
Sambit
Quote:

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Ya...
• March 18th 2011, 08:58 AM
Nafiro100
Can you guys explain how to actually do the question as I have no idea. Like the formula or something. I already have the answer I just need to know how to do it.
• March 18th 2011, 09:09 AM
Sambit
I am providing you with the probability mass function of Binomial distribution with parameters $n$ and $p$. You just need to perform a suitable summation over it, taking appropriate upper and lower limits of $k$.
• March 18th 2011, 10:37 AM
Plato
Quote:

Originally Posted by Nafiro100
Can you guys explain how to actually do the question as I have no idea. Like the formula or something. I already have the answer I just need to know how to do it.

$\displaystyle\sum\limits_{k = 4}^{10} {\binom{10}{k}\left( {0.55} \right)^k \left( {0.45} \right)^{10 - k} }=0.898005054422266$