Bayesian probability: proving $P(x|y,x) = 1$
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I have an exercise where I'm supposed to prove that $P(x|y,x) = 1$
I've come up with the following but I'm not sure if it feels right to me:
$P(x|y,x) =$
$P(x,y,x) / P(y,x) = $
$P(x|y,x)P(y|x)P(x) / P(y,x) = $
$P(x|y,x)P(y|x)P(x) / P(y|x)P(x) = $
We now have
$P(x|y,x) = P(x|y,x)$
So:
$P(x|y,x) / P(x|y,x) = P(x|y,x) / P(x|y,x) = 1$
Is this correct?
bayesian bayes-theorem
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add a comment |
$begingroup$
I have an exercise where I'm supposed to prove that $P(x|y,x) = 1$
I've come up with the following but I'm not sure if it feels right to me:
$P(x|y,x) =$
$P(x,y,x) / P(y,x) = $
$P(x|y,x)P(y|x)P(x) / P(y,x) = $
$P(x|y,x)P(y|x)P(x) / P(y|x)P(x) = $
We now have
$P(x|y,x) = P(x|y,x)$
So:
$P(x|y,x) / P(x|y,x) = P(x|y,x) / P(x|y,x) = 1$
Is this correct?
bayesian bayes-theorem
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You question is not clear. What does $p(x,y,x)$ mean?
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– user144410
Jan 16 at 13:27
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Sorry, it might be an unusual notation used in my class, it means P(x∩y∩x)
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– ronaldfisher
Jan 16 at 13:40
add a comment |
$begingroup$
I have an exercise where I'm supposed to prove that $P(x|y,x) = 1$
I've come up with the following but I'm not sure if it feels right to me:
$P(x|y,x) =$
$P(x,y,x) / P(y,x) = $
$P(x|y,x)P(y|x)P(x) / P(y,x) = $
$P(x|y,x)P(y|x)P(x) / P(y|x)P(x) = $
We now have
$P(x|y,x) = P(x|y,x)$
So:
$P(x|y,x) / P(x|y,x) = P(x|y,x) / P(x|y,x) = 1$
Is this correct?
bayesian bayes-theorem
$endgroup$
I have an exercise where I'm supposed to prove that $P(x|y,x) = 1$
I've come up with the following but I'm not sure if it feels right to me:
$P(x|y,x) =$
$P(x,y,x) / P(y,x) = $
$P(x|y,x)P(y|x)P(x) / P(y,x) = $
$P(x|y,x)P(y|x)P(x) / P(y|x)P(x) = $
We now have
$P(x|y,x) = P(x|y,x)$
So:
$P(x|y,x) / P(x|y,x) = P(x|y,x) / P(x|y,x) = 1$
Is this correct?
bayesian bayes-theorem
bayesian bayes-theorem
edited Jan 16 at 13:31
ronaldfisher
asked Jan 16 at 13:21
ronaldfisherronaldfisher
11
11
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You question is not clear. What does $p(x,y,x)$ mean?
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– user144410
Jan 16 at 13:27
$begingroup$
Sorry, it might be an unusual notation used in my class, it means P(x∩y∩x)
$endgroup$
– ronaldfisher
Jan 16 at 13:40
add a comment |
$begingroup$
You question is not clear. What does $p(x,y,x)$ mean?
$endgroup$
– user144410
Jan 16 at 13:27
$begingroup$
Sorry, it might be an unusual notation used in my class, it means P(x∩y∩x)
$endgroup$
– ronaldfisher
Jan 16 at 13:40
$begingroup$
You question is not clear. What does $p(x,y,x)$ mean?
$endgroup$
– user144410
Jan 16 at 13:27
$begingroup$
You question is not clear. What does $p(x,y,x)$ mean?
$endgroup$
– user144410
Jan 16 at 13:27
$begingroup$
Sorry, it might be an unusual notation used in my class, it means P(x∩y∩x)
$endgroup$
– ronaldfisher
Jan 16 at 13:40
$begingroup$
Sorry, it might be an unusual notation used in my class, it means P(x∩y∩x)
$endgroup$
– ronaldfisher
Jan 16 at 13:40
add a comment |
1 Answer
1
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votes
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Assuming that $P(x|y,x) = P(x|y cap x)$, just note that
$$x cap y cap x = y cap x Rightarrow P(x|y cap x) = frac{P(x cap y cap x)}{P(y cap x)} = frac{P(y cap x)}{P(y cap x)} = 1$$
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You assumed right. Thank you
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– ronaldfisher
Jan 16 at 13:36
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Assuming that $P(x|y,x) = P(x|y cap x)$, just note that
$$x cap y cap x = y cap x Rightarrow P(x|y cap x) = frac{P(x cap y cap x)}{P(y cap x)} = frac{P(y cap x)}{P(y cap x)} = 1$$
$endgroup$
$begingroup$
You assumed right. Thank you
$endgroup$
– ronaldfisher
Jan 16 at 13:36
add a comment |
$begingroup$
Assuming that $P(x|y,x) = P(x|y cap x)$, just note that
$$x cap y cap x = y cap x Rightarrow P(x|y cap x) = frac{P(x cap y cap x)}{P(y cap x)} = frac{P(y cap x)}{P(y cap x)} = 1$$
$endgroup$
$begingroup$
You assumed right. Thank you
$endgroup$
– ronaldfisher
Jan 16 at 13:36
add a comment |
$begingroup$
Assuming that $P(x|y,x) = P(x|y cap x)$, just note that
$$x cap y cap x = y cap x Rightarrow P(x|y cap x) = frac{P(x cap y cap x)}{P(y cap x)} = frac{P(y cap x)}{P(y cap x)} = 1$$
$endgroup$
Assuming that $P(x|y,x) = P(x|y cap x)$, just note that
$$x cap y cap x = y cap x Rightarrow P(x|y cap x) = frac{P(x cap y cap x)}{P(y cap x)} = frac{P(y cap x)}{P(y cap x)} = 1$$
answered Jan 16 at 13:32
trancelocationtrancelocation
12.1k1826
12.1k1826
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You assumed right. Thank you
$endgroup$
– ronaldfisher
Jan 16 at 13:36
add a comment |
$begingroup$
You assumed right. Thank you
$endgroup$
– ronaldfisher
Jan 16 at 13:36
$begingroup$
You assumed right. Thank you
$endgroup$
– ronaldfisher
Jan 16 at 13:36
$begingroup$
You assumed right. Thank you
$endgroup$
– ronaldfisher
Jan 16 at 13:36
add a comment |
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$begingroup$
You question is not clear. What does $p(x,y,x)$ mean?
$endgroup$
– user144410
Jan 16 at 13:27
$begingroup$
Sorry, it might be an unusual notation used in my class, it means P(x∩y∩x)
$endgroup$
– ronaldfisher
Jan 16 at 13:40