SOLUTION: Suppose we have a bag with $10$ slips of paper in it. Eight slips have a $7$ on them and the other two have a $9$ on them. What is the expected value of the number shown when we d

Algebra ->  Probability-and-statistics -> SOLUTION: Suppose we have a bag with $10$ slips of paper in it. Eight slips have a $7$ on them and the other two have a $9$ on them. What is the expected value of the number shown when we d      Log On


   



Question 1208667: Suppose we have a bag with $10$ slips of paper in it. Eight slips have a $7$ on them and the other two have a $9$ on them.
What is the expected value of the number shown when we draw a single slip of paper?

Answer by ikleyn(52878) About Me  (Show Source):
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Suppose we have a bag with 10 slips of paper in it. Eight slips have a 7 on them and the other two have a 9 on them.
What is the expected value of the number shown when we draw a single slip of paper?
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The probability to draw "a 7" is 8/10.

The probability to draw "a 9" is 2/10.


The expected value is  E = 7%2A%288%2F10%29 + 9%2A%282%2F10%29 = %287%2A8%2B9%2A2%29%2F10 = %2856%2B18%29%2F10 = 74%2F10 = 74%2F10 = 72%2F5 = 7.4.    ANSWER

Solved.