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koudai8
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[solved]Expected Value and Variance
Hi, I have a problem on Expected Value and Variance, and having spent hours but still couldn't figure out :(
One state lottery has 200 prizes of $1
100 prizes of $5
40 prizes of $25
13 prizes of $100
4 prizes of $350
1 prize of $1000
Assuming that 17,000 lottery tickets are issued and sold for $1
Having explained what I did for the first problem, here is the "real" problem:
Since I found the answer to the expected value indirectly, I'm a blind goose in a hailstorm on number 2...
Hi, I have a problem on Expected Value and Variance, and having spent hours but still couldn't figure out :(
One state lottery has 200 prizes of $1
100 prizes of $5
40 prizes of $25
13 prizes of $100
4 prizes of $350
1 prize of $1000
Assuming that 17,000 lottery tickets are issued and sold for $1
1. what is the lottery's expected profit per ticket
For this problem, I solved it two ways. First by summing the [products of all the numbers of tickets with their payouts], which is 5400 then (17000-5400)/17000 to get $0.6824
Second way by summing the [product of the payouts of tickets with their probabilities] = $0.6824
Having explained what I did for the first problem, here is the "real" problem:
2. What is the lottery's standard deviation of profit per ticket?
Since I found the answer to the expected value indirectly, I'm a blind goose in a hailstorm on number 2...
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