Questions on Expected Value and Standard Deviation PLEASE HELP

ksmith3894

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A bag contains 1 green ball, 2 blue balls, and 3 orange balls. Two are selected simultaneously and at random, their colors are noted. The green ball is worth $23 dollars, blue $5, and orange $1. Find expected total value and standard deviation. Well I am trying to find the right probabilities but am not getting them. I know the my expected value is the sum of all the probabilities x values. I am having trouble with probabilities mostly. I know the expected value is 12 in the book, but how?
 
A bag contains 1 green ball, 2 blue balls, and 3 orange balls. Two are selected simultaneously and at random, their colors are noted. The green ball is worth $23 dollars, blue $5, and orange $1. Find expected total value and standard deviation. Well I am trying to find the right probabilities but am not getting them. I know the my expected value is the sum of all the probabilities x values. I am having trouble with probabilities mostly. I know the expected value is 12 in the book, but how?
THere are five events: oo ob og bb bg - Order does not matter.
The probabilties are 3/15, 6/15, 3/15, 1/15, &2/15

Now can you finsh?
 
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