1. Suppose we have a bag with 8 slips of paper in it. Six of these have a 1 on them and the other two have a 3 on them. What is the expected value of the number shown when we draw a single slip of paper?
2. Suppose we have a bag with 8 slips of paper in it. Six of these have a 1 on them and the other two have a 3 on them. What is the expected value of a draw if we add one additional 3 to the bag?
3. Suppose we have a bag with 8 slips of paper in it. Six of these have a 1 on them and the other two have a 3 on them. What is the expected value of a draw if we add two 3's to the bag (instead of adding just one)?
4. Suppose we have a bag with 8 slips of paper in it. Six of these have a 1 on them and the other two have a 3 on them. How many 3's do we have to add to make the expected value equal to 2?
5. Suppose I have a bag with 8 slips of paper in it. Six of these have a 1 on them and the other two have a 3 on them. How many 3's do I have to add to make the expected value at least 2.5?
+33614 Expected value = (sum of weight*number)/(sum of weights)
So, for part 1: Expected value = (6*1 + 2*3)/(6 + 2) = 12/8 = 3/2
Part 2: Expected value = (6*1 + 3*3)/(6 + 3) = 15/9 = 5/3
See if you can now do the other parts.
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+118608 Alan has continued it here
http://web2.0calc.com/questions/i-didn-t-understand-how-you-got-this
