# Probability Distributions

• Nov 15th 2009, 09:30 AM
Bubblegum09
Probability Distributions
Hi I'm new here and I really hope you can help me. Just can't get these questions...

Brand B aspirin company decides to randomly selects 10 out of 100 doctors working in a large hospital. If 50% of the 100 doctors actually prefer brand B, what is the probability that the results of the sample will find that 9 out 10 doctors surveyed prefer brand B?

And also this one

A game consists of cutting a shuffled deck of cards and receiving the dollar value of the face value of the card. Jacks are considered to be worth 11, queens 12, kings 12 and aces 1. What is the expectation of this game?

I thought you just had to explain it or something but my teacher said that the answer was $7.00. • Nov 15th 2009, 10:26 AM BERRY For the second problem,$\displaystyle \sum_{i=1}^{n}x_{i}P(X=x_{i})$So find$\displaystyle P(X=x_{i})\$ which is the probability of selecting each card. Then multiply it by the value of that card. Do this for each card and sum it up.
• Nov 16th 2009, 12:01 PM
Bubblegum09
Thanks sooooo much!!!

Does anyone get the aspirin one?