Author Topic: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!  (Read 4721 times)

Offline SkyPilotage

  • SF Citizen
  • ***
  • Posts: 184
  • Reputation: 65535
  • Gender: Male

Offline Ghost Of Highbury

  • O_o_O lala!
  • SF Farseer
  • *******
  • Posts: 4096
  • Reputation: 41428
  • Gender: Male
  • Namaskaram!
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.
divine intervention!

Offline I Jimmy I

  • SF Citizen
  • ***
  • Posts: 207
  • Reputation: 204
  • Gender: Male
    • http://www.AWSurveys.com/HomeMain.cfm?RefID=I Jimmy I
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 :)
Avoid the last minute rush!!!!
Fail your exams NOW!!!!!
:D

Offline Ghost Of Highbury

  • O_o_O lala!
  • SF Farseer
  • *******
  • Posts: 4096
  • Reputation: 41428
  • Gender: Male
  • Namaskaram!
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?
divine intervention!

Offline EMO123

  • I Don't Know What To Do
  • SF V.I.P
  • ********
  • Posts: 5818
  • Reputation: 65534
  • Gender: Male
  • Ficticious Boy
Re: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!
« Reply #19 on: May 25, 2011, 09:23:47 am »

Offline I Jimmy I

  • SF Citizen
  • ***
  • Posts: 207
  • Reputation: 204
  • Gender: Male
    • http://www.AWSurveys.com/HomeMain.cfm?RefID=I Jimmy I
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!!!!!
:D

Offline EMO123

  • I Don't Know What To Do
  • SF V.I.P
  • ********
  • Posts: 5818
  • Reputation: 65534
  • Gender: Male
  • Ficticious Boy
Re: STATISTICS DOUBT!!! PLZ REPLY ASAP!!!
« Reply #21 on: May 25, 2011, 09:25:17 am »

Offline I Jimmy I

  • SF Citizen
  • ***
  • Posts: 207
  • Reputation: 204
  • Gender: Male
    • http://www.AWSurveys.com/HomeMain.cfm?RefID=I Jimmy I
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

  • SF Citizen
  • ***
  • Posts: 184
  • Reputation: 65535
  • Gender: Male
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

  • SF Citizen
  • ***
  • Posts: 207
  • Reputation: 204
  • Gender: Male
    • http://www.AWSurveys.com/HomeMain.cfm?RefID=I Jimmy I
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!!!!!
:D

Offline I Jimmy I

  • SF Citizen
  • ***
  • Posts: 207
  • Reputation: 204
  • Gender: Male
    • http://www.AWSurveys.com/HomeMain.cfm?RefID=I Jimmy I
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!!!!!
:D

Offline EMO123

  • I Don't Know What To Do
  • SF V.I.P
  • ********
  • Posts: 5818
  • Reputation: 65534
  • Gender: Male
  • Ficticious Boy
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

  • I Don't Know What To Do
  • SF V.I.P
  • ********
  • Posts: 5818
  • Reputation: 65534
  • Gender: Male
  • Ficticious Boy
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

  • O_o_O lala!
  • SF Farseer
  • *******
  • Posts: 4096
  • Reputation: 41428
  • Gender: Male
  • Namaskaram!
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
divine intervention!

Offline I Jimmy I

  • SF Citizen
  • ***
  • Posts: 207
  • Reputation: 204
  • Gender: Male
    • http://www.AWSurveys.com/HomeMain.cfm?RefID=I Jimmy I
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