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Math Help - Need probability and stats help please!!

  1. #1
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    Need probability and stats help please!!

    Given the independant variable with mean =ux=120 and uy=300 The St. Dev is Qx= 12, Qy=16. What is the mean and ST.D of each veriibles
    a) 0.8y+20 b)2x-100 c)x+2y

    Please explain how you did this and show steps so that i can understand how it was done!!

    #2. Lets say 13% of ppl are lift handed, if we randomly test 5 persons, find the probability of these:
    a) some lefties among 5 ppl
    b) there are exaclty three left handed ppl in the team
    c) there are at least three lefted hands in the team
    d)there are less than 3 lefties in the team

    Again please explain how you did this thanks!
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  2. #2
    MHF Contributor
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    Re: Need probability and stats help please!!

    Hey RozayAce.

    Hint: E[X+Y] = E[X] + E[Y] and Var[X+Y] = Var[X] + Var[Y] if X and Y are independent. Also Var[aX] = a^2*Var[X] and E[aX] = a*E[X].
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