Two Problems

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Two Problems
Message posted by Carol on November 18, 2000 at 12:00 AM (ET)

I have two problems that are giving me fits. The firt one is:

The probability that any single ticket is a winning ticket is 0.0000000715. The jackpot is hugh ($50 million, and there were 25 million tickets sold. How many winning tickets would you expect to be among the 25 million tickets sold and also what is the probability that there are 2 winning tickets.

Second problem:

There is roughly an 80% chance that a person who is now age 20 will live to be age 65. How many of them would you expect to live to age 65?

Thank you.

READERS RESPOND:
(In chronological order. Most recent at the bottom.)

Re: Two Problems
Message posted by JG on November 19, 2000 at 12:00 AM (ET)

For part a. , using your data and making the usual assumptions we get a poisson distribution with average of 1.8 so that the probabilities for 1,2,3 tickets are .17,.30,.27 etc.

For part b. you have to say which population you are taking about. The proportion of 20 year olds and the mortality rate vary widely all over the world. For some populatins living past the age of 20 is quite problamatic.

Re: Two Problems
Message posted by Carol on November 19, 2000 at 12:00 AM (ET)

Thank you for helping me with part a. On part b, the data was taken from the U.S. National Center for Health Statistics in Vital Statistics of the United States. Does that make a difference on how this problem is solved, or are you saving that this problem can not be solved with the information given?

Thanks again.

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