Author Topic: Maths help paper 1 & 6 :D normal distribution :D :D :D  (Read 1217 times)

Offline superduper2009

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Maths help paper 1 & 6 :D normal distribution :D :D :D
« on: April 23, 2010, 04:39:59 pm »
Can someone solve the following question for me please ->
MAY/June 09 q 3 for paper 1 i.e. pure maths 1.... with all the working...
Also can you please explain when to use continuity correction and when not to use it for normal distribution in statistics
« Last Edit: April 23, 2010, 08:24:42 pm by superduper2009 »

Offline astarmathsandphysics

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Re: Maths help paper 1 & 6 :D normal distribution :D :D :D
« Reply #1 on: April 23, 2010, 05:28:40 pm »
2 hours

Offline astarmathsandphysics

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Re: Maths help paper 1 & 6 :D normal distribution :D :D :D
« Reply #2 on: April 23, 2010, 07:07:44 pm »
For what paper and board

Offline superduper2009

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Re: Maths help paper 1 & 6 :D normal distribution :D :D :D
« Reply #3 on: April 23, 2010, 08:23:00 pm »
paper 1 cie
thanks in advance

Offline astarmathsandphysics

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Re: Maths help paper 1 & 6 :D normal distribution :D :D :D
« Reply #4 on: April 23, 2010, 08:44:56 pm »
a)(2+3x)^5 =5C0*2^5*(3x)^0+5C1*2^4*(3x)^1+5C2*2^3*(3x)^2=32+240x+720x^2
b)(1+ax)(2+3x)^5 =(1+ax)(32+240x+720x^2)=..+x^2(720+240a)+...
since the x^2 term is 0 720+240a=0 so a=-3


Offline astarmathsandphysics

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Offline superduper2009

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Re: Maths help paper 1 & 6 :D normal distribution :D :D :D
« Reply #6 on: April 23, 2010, 09:03:56 pm »
Thank you sooo much..
can you help me with one more thing...
in the same paper...can you please do question number 2 as well...
thanks in advance
+rep

Offline astarmathsandphysics

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Re: Maths help paper 1 & 6 :D normal distribution :D :D :D
« Reply #7 on: April 23, 2010, 09:09:37 pm »
kx-4=x^2 -2x
x^2-(2+k)+4=0
2 distinct points so b^2 -4ac>0
(-(2+k))^2 -4*1*4>0
4+4k+k^2-16>0
k^2+4k-12>0
(k+6)(k-2)>0
k<-6 or k>2

see also

Offline superduper2009

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Re: Maths help paper 1 & 6 :D normal distribution :D :D :D
« Reply #8 on: April 23, 2010, 09:19:27 pm »
That was fast...
Thanks a lot :D
By the way ur amazing ... and thank you LOADS & LOADS for this amazing website and freeexampapers.com...... they helped me out ... ALOT ...and i really mean ALOT

Offline astarmathsandphysics

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Re: Maths help paper 1 & 6 :D normal distribution :D :D :D
« Reply #9 on: April 23, 2010, 09:22:25 pm »
We try

Offline superduper2009

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Re: Maths help paper 1 & 6 :D normal distribution :D :D :D
« Reply #10 on: April 23, 2010, 09:30:10 pm »
one more quick question :P
cie october november 2008 paper 6..... question 1
I get the mean...but i get the standard deviation wrong...
can you please explain how to calculate the standard deviation

EDIT
STOP STOP... I GOT IT I WASN'T SQUARING THE MEAN SORRY SORRY  :D
« Last Edit: April 23, 2010, 09:33:10 pm by superduper2009 »

Offline astarmathsandphysics

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Re: Maths help paper 1 & 6 :D normal distribution :D :D :D
« Reply #11 on: April 23, 2010, 09:34:24 pm »
Use \sigma =sqrt{\frac {\sum x^2 -n { \bar x}^2}{n-1}}
where \bar x =\frac {\sum x}{n}
« Last Edit: April 23, 2010, 09:39:10 pm by astarmathsandphysics »

Offline superduper2009

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Re: Maths help paper 1 & 6 :D normal distribution :D :D :D
« Reply #12 on: April 23, 2010, 09:36:54 pm »
thank you sooooooooooooooooooooo much :D :D :D :D :D :D i really really appreciate it

Offline astarmathsandphysics

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Re: Maths help paper 1 & 6 :D normal distribution :D :D :D
« Reply #13 on: April 23, 2010, 09:40:06 pm »
Done now. Every time I try something new with the version of latex on the forum I have to do some pfaffing around