Author Topic: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!  (Read 4745 times)

Offline SkyPilotage

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Offline Ghost Of Highbury

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Re: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!
« Reply #16 on: May 24, 2011, 07:23:38 pm »
To my knowledge, using the normal distribution to calculate the probability of a random variable X > q (where q is an integer) is the same as
the probability of x >=q. So by mistake, if u make an error in the sign, your final answer won't change. However, you may lose marks for
not using the correct sign if the question clearly stated the conditions.
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Offline I Jimmy I

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Re: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!
« Reply #17 on: May 25, 2011, 09:09:11 am »
P(X>10) = P(V>10.5) when using C.C
P(X>=10) = P(V>=9.5) when using C.C

So it does matter a LOT :)
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Offline Ghost Of Highbury

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Re: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!
« Reply #18 on: May 25, 2011, 09:19:33 am »
P(X>10) = P(V>10.5) when using C.C
P(X>=10) = P(V>=9.5) when using C.C

So it does matter a LOT :)

Yes, for normal distribution model, it does matter agreed. :)

What's C.C?
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Offline EMO123

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Re: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!
« Reply #19 on: May 25, 2011, 09:23:47 am »

Offline I Jimmy I

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Re: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!
« Reply #20 on: May 25, 2011, 09:24:32 am »
what is this Tyvm????
Thank You Very Much :o
Avoid the last minute rush!!!!
Fail your exams NOW!!!!!
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Offline EMO123

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Re: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!
« Reply #21 on: May 25, 2011, 09:25:17 am »

Offline I Jimmy I

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Re: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!
« Reply #22 on: May 25, 2011, 09:41:14 am »
Avoid the last minute rush!!!!
Fail your exams NOW!!!!!
:D

Offline SkyPilotage

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Re: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!
« Reply #23 on: May 25, 2011, 09:43:33 am »
Yes, for normal distribution model, it does matter agreed. :)

What's C.C?
Continuity Correction When aproximating a B.D as a Normal D....

Offline I Jimmy I

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Re: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!
« Reply #24 on: May 25, 2011, 09:56:40 am »
Yes, for normal distribution model, it does matter agreed. :)

What's C.C?

Continuity Correction. Its used when Binomial distributions are converted to Normal distributions when np and nq>5
So u either add or subtract 0.5 to the given P(X>n)

P.S "n" in the P(X>n) is any constant :)
Avoid the last minute rush!!!!
Fail your exams NOW!!!!!
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Offline I Jimmy I

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Re: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!
« Reply #25 on: May 25, 2011, 10:00:55 am »
Ok guys, I have another doubt. :(

Question 5(iii) and (iv) of M/J 2010 ----2nd variant-----

Given, P(Q)= 1/24
P(R)=1/9

Question is,
(iii)Are events Q and R exclusive? Justify your answer.
(iv)Are events Q and R independent? Justify your answer.

If my memory serves me well then exclusive is (A.B)=0 and independent is (A.B) NOT= 0
Marking Scheme says that Q and R are exclusive but ( 1/24*1/9) isnt 0 so HOW...?
Avoid the last minute rush!!!!
Fail your exams NOW!!!!!
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Offline EMO123

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Re: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!
« Reply #26 on: May 25, 2011, 10:13:08 am »
Ok guys, I have another doubt. :(

Question 5(iii) and (iv) of M/J 2010 ----2nd variant-----

Given, P(Q)= 1/24
P(R)=1/9

Question is,
(iii)Are events Q and R exclusive? Justify your answer.
(iv)Are events Q and R independent? Justify your answer.

If my memory serves me well then exclusive is (A.B)=0 and independent is (A.B) NOT= 0
Marking Scheme says that Q and R are exclusive but ( 1/24*1/9) isnt 0 so HOW...?
5(iii)
if P(R and Q)=0
then it is Exclusive

Offline EMO123

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Re: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!
« Reply #27 on: May 25, 2011, 10:14:29 am »
Ok guys, I have another doubt. :(

Question 5(iii) and (iv) of M/J 2010 ----2nd variant-----

Given, P(Q)= 1/24
P(R)=1/9

Question is,
(iii)Are events Q and R exclusive? Justify your answer.
(iv)Are events Q and R independent? Justify your answer.

If my memory serves me well then exclusive is (A.B)=0 and independent is (A.B) NOT= 0
Marking Scheme says that Q and R are exclusive but ( 1/24*1/9) isnt 0 so HOW...?
5 (iv)
if P(R and Q)=P(R) * P(Q)
then it is Independent
But if it is not equal to it then it is not independent

Offline Ghost Of Highbury

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Re: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!
« Reply #28 on: May 25, 2011, 10:19:07 am »
Continuity Correction. Its used when Binomial distributions are converted to Normal distributions when np and nq>5
So u either add or subtract 0.5 to the given P(X>n)

P.S "n" in the P(X>n) is any constant :)

Ah ok, thanks
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Offline I Jimmy I

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Re: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!
« Reply #29 on: May 25, 2011, 10:48:01 am »
5(iii)
if P(R and Q)=0
then it is Exclusive

thats what I thought but P(R)*P(Q) is not 0 even tho the Marking scheme said the opposite...
Avoid the last minute rush!!!!
Fail your exams NOW!!!!!
:D