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    I'm a tad stuck on this question and was wondering if anyone could help me out with a step by step example? Thankyou!

    The random variable T has a mean of 20 and a standard deviation of 5.
    It is required to scale T by using the transformation S = 3T + 4
    Find E(S) and Var(S)
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    it sounds more like S1 or S2 than C2 ?
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    (Original post by Kaylalou_21)
    I'm a tad stuck on this question and was wondering if anyone could help me out with a step by step example? Thankyou!

    The random variable T has a mean of 20 and a standard deviation of 5.
    It is required to scale T by using the transformation S = 3T + 4
    Find E(S) and Var(S)
    E(3T +4) = E(3T) + 4 = 3E(T)

    Var(3T+4) = Var(3T) = 3^2Var(T) = 9Var(T)

    You know E(T) = 20 and Vart(T) = 5^2 = 25.
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    i f Y = 5X - 4

    then E(Y) = 5E(X) - 4

    & Var(Y) = 25Var(X)
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    Oh, and I'm moving this to maths (and correcting the title to S2, which is what I think you mean).
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    (Original post by the bear)
    it sounds more like S1 or S2 than C2 ?
    Oops typo, it is S1
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    (Original post by Zacken)
    E(3T +4) = E(3T) + 4 = 3E(T)

    Var(3T+4) = Var(3T) = 3^2Var(T) = 9Var(T)

    You know E(T) = 20 and Vart(T) = 5^2 = 25.
    Thankyou, this was really helpful and I apologise I just joined so I'm not quite sure how to navigate this site properly yet haha
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    (Original post by Kaylalou_21)
    Thankyou, this was really helpful and I apologise I just joined so I'm not quite sure how to navigate this site properly yet haha
    Glad it was helpful, don't worry about it - just remember that in the future, maths questions go in maths study help. :-)
 
 
 
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