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Alevel help with further maths

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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Reply 1
I have been stuck on this problem for ages... does anyone have any idea how to even start solving it?
Reply 2
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!


Screen Shot 2018-02-21 at 13.33.18.png
I've done this- i think this is first principle enough but if not I can try and prove parts of this solution too.
Reply 3
It is! Thank you very much! You saved my life
Reply 4
I also have another question on this paper... nice handwriting by the wat
Reply 5
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Reply 6
I managed to proof the first part but can you give me any pointers for part b?
Reply 7
Original post by ZaraHuss
Screen Shot 2018-02-21 at 13.33.18.png
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?
Reply 8
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)
Reply 9
I am doing AQA. I will check our formulae booklet! Again thank you very much
Original post by Ioanna13
E48EA11A-3F97-45EB-A559-EF8968FD1BBB.jpg.jpeg


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.
Reply 11
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Reply 12
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Reply 13
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Original post by Ioanna13
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Is this better?
Original post by Ioanna13
It is! Thank you very much! You saved my life


He saved your life?
Reply 15
Original post by joyoustele
He saved your life?


Oh yeah hahahahhaha
This is Further Maths 2017?

I swear it's core 1, core 2, FP1, FP2? You don't have to do statistics.
Reply 17
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
Reply 18
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.
Reply 19
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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