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Edexcel S2 - 27th June 2016 AM

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Original post by SeanFM
Correct (though if you sketch the half of the distribution that you do know, it may help to..save some integrating, is all I will say).


Perhaps something is going wrong in the calculation or writing things down?


I've tried a lot here - can't seem to get an integer for K?
Original post by iMacJack
I've tried a lot here - can't seem to get an integer for K?


Working, please. Otherwise I'm not sure how to help. I wouldn't put it past me to have made a mistake in the question but I've checked a few times, so I'm not sure :erm:
(edited 7 years ago)
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imran_
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Original post by r3h4f
I would have thought that it would be P(X<=8) because CR is X>=9?


can u explain how please? i dont get the entire question
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SSD07
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Screen Shot 2016-06-26 at 14.37.56.pngSorry i know this question has already been asked, but i just tried doing it myself and I'm a bit confused, its from June 2010.

Basically i worked out that:
2x+2y=20
and because your trying to find P(Y>6)
P(10-x>6) so therefore
P(X<4) = 1/2 but why isn't this the answer? why do you have to add on a 1/6 as the answer is 2/3 ??
Original post by SeanFM
Working, please. Otherwise I'm not sure how to help. I wouldn't put it past me to have made a mistake in the question but I've checked a few times, so I'm not sure :erm:


Here's my integration method ImageUploadedByStudent Room1466948596.711281.jpg


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how do you go about solving
d^4-8d^2+8=0

it was on the june 2014(r) paper
Original post by Lilly1234567890
how do you go about solving
d^4-8d^2+8=0

it was on the june 2014(r) paper


Substitute.

Let y = d^2
I dont get what theyve done in Q3b June 2013
I also dont get questions with Var like Var(3-2X)

E.g. If uniform dist. has intervals (b,4b) Find Var(3-2X)
Original post by fpmaniac
I also dont get questions with Var like Var(3-2X)

E.g. If uniform dist. has intervals (b,4b) Find Var(3-2X)


Var(3-2X) = 4Var(X)
anybody got links to jan 16 ial?
Original post by fpmaniac
I also dont get questions with Var like Var(3-2X)

E.g. If uniform dist. has intervals (b,4b) Find Var(3-2X)


Varx = 9b^2/12

var(3-2x) = 4Var(x) = 36b^2/12 = 3b^2?
Original post by fpmaniac
I also dont get questions with Var like Var(3-2X)

E.g. If uniform dist. has intervals (b,4b) Find Var(3-2X)


Did you do s1? Because you square the number in front of the X and times Var(X) by it. To work out VarX of a uniform distribution use the formula book
Original post by fpmaniac
I also dont get questions with Var like Var(3-2X)

E.g. If uniform dist. has intervals (b,4b) Find Var(3-2X)

a^2Var(X)

Then for continuouse uniform distribution Var(X)=((b-a)^2)/12

I think lol
Original post by iMacJack
Add five to both sides of the inequality and work it out? Take care of the 8 in the inequality though, as the maximum value is 6, so adjust the inequality taking note of this


Thank you!!? ^^

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Original post by iMacJack
Varx = 9b^2/12

var(3-2x) = 4Var(x) = 36b^2/12 = 3b^2?


Original post by Dentistry101
Did you do s1? Because you square the number in front of the X and times Var(X) by it. To work out VarX of a uniform distribution use the formula book


Thanks. And I didnt do S1
Uniform Distribution.png

How do you do part (c) (d) and (e) ?
Original post by SeanFM
If -3 < X - 5 < 3 then a < X < b where a =... and b =....


Thank you :smile:

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Original post by NotNotBatman
Uniform Distribution.png

How do you do part (c) (d) and (e) ?


How do you find R in terms of X?

(Hint: it is the area of a rectangle with one length being ... and the other ...)
jan 16 ial s2 anybody got it?

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