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    The random variable X takes values 2,4,6,...1000 with equal probabilities. Find from first principles the variance of X.

    Anyone that can help me with this problem? It would be much appreciated!
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    I have been stuck on this problem for ages... does anyone have any idea how to even start solving it?
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    (Original post by Ioanna13)
    The random variable X takes values 2,4,6,...1000 with equal probabilities. Find from first principles the variance of X.

    Anyone that can help me with this problem? It would be much appreciated!
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    I've done this- i think this is first principle enough but if not I can try and prove parts of this solution too.
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    It is! Thank you very much! You saved my life
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    I also have another question on this paper... nice handwriting by the wat
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    I managed to proof the first part but can you give me any pointers for part b?
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    (Original post by ZaraHuss)
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    I've done this- i think this is first principle enough but if not I can try and prove parts of this solution too.
    Also can you pleeeaaasee explain to me the part of Σ/n? Why did you do that?
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    (Original post by Ioanna13)
    Also can you pleeeaaasee explain to me the part of Σ/n? Why did you do that?
    So the expected value of x is just summation of all the x values divided by the number there are. That can be written as Σ/n. Similarly for x^2! The formulae that follow this I learnt in Edexcel FP1 (I don't know if you're doing a different exam board but it's in the formula book for Edexcel)
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    I am doing AQA. I will check our formulae booklet! Again thank you very much
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    (Original post by Ioanna13)
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    The quality isn't very good of this- can you just send the question, or with a better resolution and i can have a go.
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    (Original post by Ioanna13)
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    Is this better?
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    (Original post by Ioanna13)
    It is! Thank you very much! You saved my life
    He saved your life?
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    (Original post by joyoustele)
    He saved your life?
    Oh yeah hahahahhaha
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    This is Further Maths 2017?

    I swear it's core 1, core 2, FP1, FP2? You don't have to do statistics.
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    (Original post by thekidwhogames)
    This is Further Maths 2017?

    I swear it's core 1, core 2, FP1, FP2? You don't have to do statistics.
    I am doing Further Maths AQA 2018, it is the new linear course
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    (Original post by thekidwhogames)
    This is Further Maths 2017?

    I swear it's core 1, core 2, FP1, FP2? You don't have to do statistics.
    In the new A-Level Maths you do. Statistics in FM is optional.
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    (Original post by Black Water)
    In the new A-Level Maths you do. Statistics in FM is optional.
    Are you sure? Because it is a very new Alevel
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