Question 847615: I'm a bit confused on exactly what these are asking me. I am posting the question along with where I am in the answer. I don't know if I'm way off base here.
Questions:
You have a bag of 500 marbles. You were told by the clerk when you got the bag that they are 99% green and 1% red. If you pull out 5 marbles at random and they are 4 red and 1 green, what does that tell you?
First I am looking at the probability of pulling out a red marble in the first random draw. If the clerk was correct then out of 500 marbles exactly 5 should be red. I then used the combination rule since the marbles are all distinct and each marble without replacement is selected at random. I found 255,244,687,600 possible combinations of marble selection. The clerk is incorrect because it is unlikely 80% of the red marbles would be pulled out in the first draw.
(If I am way off base here, please steer me back).
Thank you!!
Answer by richwmiller(17219)   (Show Source):
You can put this solution on YOUR website! Probability doesn't tell us what will happen next.
Yes it is unlikely to pick 4 red marbles when there are only 5. However it is still possible.
What does that tell you? Don't depend on the odds in one instance. Over the long run, you SHOULD make out ok.
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