expected value math questions
March 28th, 2014 at 1:09:26 PM
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1. In a bag, there are 55 counters. One is marked with a 1, two marked with a 2, . . . , ten marked with a 10. A person draws a counter at random from the bag and is to receive as many euro as the number marked on the counter. Find the expected value of the amount the person will receive.
2. The prize for winning a lottery is as follows. A three-digit number is produced by randomly rearranging the digits 1, 2, 3 and the winner is to receive an amount in dollars equal to the number obtained (e.g. 231dollars). Find the expected value of the amount the person will receive.
(Note that the numbers produced have three different digits.)
3. A bag contains five counters, marked with the numbers 1 to 5. A person draws two counters from the bag and is to obtain an amount in dollars equal to the product of the two numbers shown on the counters.
Find the expected value and variance of the amount the person will obtain.
PLEASE HELP with solutions to above questions?
Thanks
2. The prize for winning a lottery is as follows. A three-digit number is produced by randomly rearranging the digits 1, 2, 3 and the winner is to receive an amount in dollars equal to the number obtained (e.g. 231dollars). Find the expected value of the amount the person will receive.
(Note that the numbers produced have three different digits.)
3. A bag contains five counters, marked with the numbers 1 to 5. A person draws two counters from the bag and is to obtain an amount in dollars equal to the product of the two numbers shown on the counters.
Find the expected value and variance of the amount the person will obtain.
PLEASE HELP with solutions to above questions?
Thanks
March 28th, 2014 at 1:16:06 PM
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I'd suggest that you do your own homework.
Here's a hint, though: Expected value is just a mean (arithmetic average).
Here's a hint, though: Expected value is just a mean (arithmetic average).
March 29th, 2014 at 7:20:26 AM
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http://en.wikipedia.org/wiki/Expected_value#Definition
Identify all possible outcomes for the random variable you are interested in. Second figure out the probabilities for each outcome (this is probably where the majority of the work is). Then multiply the values and the probabilities. Finally sum it all up.
Identify all possible outcomes for the random variable you are interested in. Second figure out the probabilities for each outcome (this is probably where the majority of the work is). Then multiply the values and the probabilities. Finally sum it all up.
