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  #1  
Old 08-10-2011
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Stats worried about probability question!!

hey friends i have problem....

the question which asking if patient survive for two year then what is the probability that patient will survive 4 years.....some are saying multiply all four yer probability..some are saying multiply only 3rd and fourth year probability...can anyone explain basic fundamental to give answer of such type of questions...



THANKS A LOT IN ADVANCE..PLEASE GUYS HELP ME...
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Old 08-10-2011
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Originally Posted by dr.digant View Post
hey friends i have problem....

the question which asking if patient survive for two year then what is the probability that patient will survive 4 years.....some are saying multiply all four yer probability..some are saying multiply only 3rd and fourth year probability...can anyone explain basic fundamental to give answer of such type of questions...



THANKS A LOT IN ADVANCE..PLEASE GUYS HELP ME...
First you need the probability of survival. Then this becomes just a conditional probability (given that the patient survived 2 years, what is the probability...).

The probability that event B occurs, given that event A has already occurred is
P(B|A) = P(A and B) / P(A)

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  #3  
Old 08-10-2011
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Originally Posted by bebix View Post
First you need the probability of survival. Then this becomes just a conditional probability (given that the patient survived 2 years, what is the probability...).

The probability that event B occurs, given that event A has already occurred is
P(B|A) = P(A and B) / P(A)

hey bebix dint get you....can u explain me in detail????...with example????...are u going to give nbme 4???..bcoz i had question in nbme 4...if u r not giving nbme 4 then i can tell u actual question..so u can explain me better!!!!
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Old 08-10-2011
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Originally Posted by bebix View Post
First you need the probability of survival. Then this becomes just a conditional probability (given that the patient survived 2 years, what is the probability...).

The probability that event B occurs, given that event A has already occurred is
P(B|A) = P(A and B) / P(A)

u had told that probability of A and B.....P(A and B)...MEANS???...we should add or multiply???..
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  #5  
Old 08-10-2011
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hey bebix dint get you....can u explain me in detail????...with example????...are u going to give nbme 4???..bcoz i had question in nbme 4...if u r not giving nbme 4 then i can tell u actual question..so u can explain me better!!!!
just send me a pm
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  #6  
Old 08-10-2011
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just send me a pm
hey bebix have u got private message???
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  #7  
Old 08-10-2011
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hey bebix have u got private message???
yup...answer is C)
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  #8  
Old 08-10-2011
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yup...answer is C)
hey bebix i have sent u another private message...if u knw the answer please explain me..thanks a lot!!!


and thanks for nice explaination of previous question too
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Old 08-10-2011
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yup...answer is C)
its also NBME 4 quesstion...
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  #10  
Old 08-11-2011
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yup...answer is C)
hey bebix please reply the another question which i have sent u in private message...THANKS
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Old 01-05-2017
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Originally Posted by dr.digant View Post
hey friends i have problem....

the question which asking if patient survive for two year then what is the probability that patient will survive 4 years.....some are saying multiply all four yer probability..some are saying multiply only 3rd and fourth year probability...can anyone explain basic fundamental to give answer of such type of questions...



THANKS A LOT IN ADVANCE..PLEASE GUYS HELP ME...
It is conditional probability. Use this formula:P(A|B) = P(B and A) / P(B) and VENN diagram. In this formula P(A andB) is joint area of VENN diagram, in this case 4 year survival is the part of the 2 year survival .Joint area equal the probability of 4 year survival. Probability of 4 year survial= joint area probability(4 year) / 2 year survival
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