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Sampling - the variable of X

  1. Oct 16, 2014 #1
    1. The problem statement, all variables and given/known data

    A bag contains a large number of coins comprises of 1 cent and 5 cents coins in the ration of 1:3

    find the man and variance of the values of coins..
    i have attached the sample ans here. i dont understand why the value of '2' is used?? why not '5' ...for me '5' represent 5 cents.
    2. Relevant equations


    3. The attempt at a solution
     

    Attached Files:

  2. jcsd
  3. Oct 16, 2014 #2

    Mark44

    Staff: Mentor

    I think there is a typo in the sample answer. The mean should be 1*1/4 + 5*3/4 = 1/4 + 15/14 = 16/4 = 4 (cents).
     
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