Conditional Probability Mean












0












$begingroup$


I have a continuous random variable Y with its mean conditioned on another random (discrete) variable X as follows.



m0 = E(Y|X=0) = 12
m1 = 3
m2 = 7



and I want to find mY|X<2 = E(Y|X<2). Is this intuitive. Because supposedly it is not and my immediate reaction is to say it is simply the E(Y|X = 0) + E(Y|X = 1)



Thanks in advance



EDIT: I do have some information on the variable X but it seemed to not be helpful to me.



p0 = P(X = 0) = 0.2
p1 = 0.7
p2 = 0.1










share|cite|improve this question











$endgroup$












  • $begingroup$
    I'm not sure you can find $E[Y mid X<2]$ only using $E[Y mid X=x]$ for $x=0,1,2$. I think you need more information about the distribution of $X$.
    $endgroup$
    – angryavian
    Jan 13 at 21:23










  • $begingroup$
    I added some information but do you think it's relevant?
    $endgroup$
    – A.Code.1
    Jan 13 at 21:27










  • $begingroup$
    @A.Code.1 Is $E(X)=3$, or what is meant by $m_1$ and $m_2$?
    $endgroup$
    – callculus
    Jan 13 at 21:33












  • $begingroup$
    m1 = E(Y|X = 1) and m2 = E(Y|X =2)
    $endgroup$
    – A.Code.1
    Jan 13 at 21:37










  • $begingroup$
    @angryavian I have to admit I´m not sure with my answer. I should delete it. You should write an answer.
    $endgroup$
    – callculus
    Jan 13 at 21:55
















0












$begingroup$


I have a continuous random variable Y with its mean conditioned on another random (discrete) variable X as follows.



m0 = E(Y|X=0) = 12
m1 = 3
m2 = 7



and I want to find mY|X<2 = E(Y|X<2). Is this intuitive. Because supposedly it is not and my immediate reaction is to say it is simply the E(Y|X = 0) + E(Y|X = 1)



Thanks in advance



EDIT: I do have some information on the variable X but it seemed to not be helpful to me.



p0 = P(X = 0) = 0.2
p1 = 0.7
p2 = 0.1










share|cite|improve this question











$endgroup$












  • $begingroup$
    I'm not sure you can find $E[Y mid X<2]$ only using $E[Y mid X=x]$ for $x=0,1,2$. I think you need more information about the distribution of $X$.
    $endgroup$
    – angryavian
    Jan 13 at 21:23










  • $begingroup$
    I added some information but do you think it's relevant?
    $endgroup$
    – A.Code.1
    Jan 13 at 21:27










  • $begingroup$
    @A.Code.1 Is $E(X)=3$, or what is meant by $m_1$ and $m_2$?
    $endgroup$
    – callculus
    Jan 13 at 21:33












  • $begingroup$
    m1 = E(Y|X = 1) and m2 = E(Y|X =2)
    $endgroup$
    – A.Code.1
    Jan 13 at 21:37










  • $begingroup$
    @angryavian I have to admit I´m not sure with my answer. I should delete it. You should write an answer.
    $endgroup$
    – callculus
    Jan 13 at 21:55














0












0








0





$begingroup$


I have a continuous random variable Y with its mean conditioned on another random (discrete) variable X as follows.



m0 = E(Y|X=0) = 12
m1 = 3
m2 = 7



and I want to find mY|X<2 = E(Y|X<2). Is this intuitive. Because supposedly it is not and my immediate reaction is to say it is simply the E(Y|X = 0) + E(Y|X = 1)



Thanks in advance



EDIT: I do have some information on the variable X but it seemed to not be helpful to me.



p0 = P(X = 0) = 0.2
p1 = 0.7
p2 = 0.1










share|cite|improve this question











$endgroup$




I have a continuous random variable Y with its mean conditioned on another random (discrete) variable X as follows.



m0 = E(Y|X=0) = 12
m1 = 3
m2 = 7



and I want to find mY|X<2 = E(Y|X<2). Is this intuitive. Because supposedly it is not and my immediate reaction is to say it is simply the E(Y|X = 0) + E(Y|X = 1)



Thanks in advance



EDIT: I do have some information on the variable X but it seemed to not be helpful to me.



p0 = P(X = 0) = 0.2
p1 = 0.7
p2 = 0.1







probability probability-theory probability-distributions






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 13 at 21:26







A.Code.1

















asked Jan 13 at 21:17









A.Code.1A.Code.1

32




32












  • $begingroup$
    I'm not sure you can find $E[Y mid X<2]$ only using $E[Y mid X=x]$ for $x=0,1,2$. I think you need more information about the distribution of $X$.
    $endgroup$
    – angryavian
    Jan 13 at 21:23










  • $begingroup$
    I added some information but do you think it's relevant?
    $endgroup$
    – A.Code.1
    Jan 13 at 21:27










  • $begingroup$
    @A.Code.1 Is $E(X)=3$, or what is meant by $m_1$ and $m_2$?
    $endgroup$
    – callculus
    Jan 13 at 21:33












  • $begingroup$
    m1 = E(Y|X = 1) and m2 = E(Y|X =2)
    $endgroup$
    – A.Code.1
    Jan 13 at 21:37










  • $begingroup$
    @angryavian I have to admit I´m not sure with my answer. I should delete it. You should write an answer.
    $endgroup$
    – callculus
    Jan 13 at 21:55


















  • $begingroup$
    I'm not sure you can find $E[Y mid X<2]$ only using $E[Y mid X=x]$ for $x=0,1,2$. I think you need more information about the distribution of $X$.
    $endgroup$
    – angryavian
    Jan 13 at 21:23










  • $begingroup$
    I added some information but do you think it's relevant?
    $endgroup$
    – A.Code.1
    Jan 13 at 21:27










  • $begingroup$
    @A.Code.1 Is $E(X)=3$, or what is meant by $m_1$ and $m_2$?
    $endgroup$
    – callculus
    Jan 13 at 21:33












  • $begingroup$
    m1 = E(Y|X = 1) and m2 = E(Y|X =2)
    $endgroup$
    – A.Code.1
    Jan 13 at 21:37










  • $begingroup$
    @angryavian I have to admit I´m not sure with my answer. I should delete it. You should write an answer.
    $endgroup$
    – callculus
    Jan 13 at 21:55
















$begingroup$
I'm not sure you can find $E[Y mid X<2]$ only using $E[Y mid X=x]$ for $x=0,1,2$. I think you need more information about the distribution of $X$.
$endgroup$
– angryavian
Jan 13 at 21:23




$begingroup$
I'm not sure you can find $E[Y mid X<2]$ only using $E[Y mid X=x]$ for $x=0,1,2$. I think you need more information about the distribution of $X$.
$endgroup$
– angryavian
Jan 13 at 21:23












$begingroup$
I added some information but do you think it's relevant?
$endgroup$
– A.Code.1
Jan 13 at 21:27




$begingroup$
I added some information but do you think it's relevant?
$endgroup$
– A.Code.1
Jan 13 at 21:27












$begingroup$
@A.Code.1 Is $E(X)=3$, or what is meant by $m_1$ and $m_2$?
$endgroup$
– callculus
Jan 13 at 21:33






$begingroup$
@A.Code.1 Is $E(X)=3$, or what is meant by $m_1$ and $m_2$?
$endgroup$
– callculus
Jan 13 at 21:33














$begingroup$
m1 = E(Y|X = 1) and m2 = E(Y|X =2)
$endgroup$
– A.Code.1
Jan 13 at 21:37




$begingroup$
m1 = E(Y|X = 1) and m2 = E(Y|X =2)
$endgroup$
– A.Code.1
Jan 13 at 21:37












$begingroup$
@angryavian I have to admit I´m not sure with my answer. I should delete it. You should write an answer.
$endgroup$
– callculus
Jan 13 at 21:55




$begingroup$
@angryavian I have to admit I´m not sure with my answer. I should delete it. You should write an answer.
$endgroup$
– callculus
Jan 13 at 21:55










1 Answer
1






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oldest

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1












$begingroup$

The conditional expectation of $Y$ given an event $A$ is
$$E[Y mid A] = frac{E[Y cdot 1_A]}{P(A)},$$
where $1_A$ is an indicator random variable that equals $1$ when the event $A$ occurs, and equals zero otherwise.



In your case you have $A = {X < 2}$.
The denominator is $P(A) = P(X=0) + P(X=1)$.
By the law of total expectation, the numerator is
$$E[Y cdot 1_A] = sum_{x=0}^2 E[Y cdot 1_A mid X=x] P(X=x) = E[Y mid X=0] P(X=0) + E[Y mid X=1] P(X=1).$$






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Nice answer, angryavian.
    $endgroup$
    – callculus
    Jan 13 at 22:52











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1 Answer
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active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









1












$begingroup$

The conditional expectation of $Y$ given an event $A$ is
$$E[Y mid A] = frac{E[Y cdot 1_A]}{P(A)},$$
where $1_A$ is an indicator random variable that equals $1$ when the event $A$ occurs, and equals zero otherwise.



In your case you have $A = {X < 2}$.
The denominator is $P(A) = P(X=0) + P(X=1)$.
By the law of total expectation, the numerator is
$$E[Y cdot 1_A] = sum_{x=0}^2 E[Y cdot 1_A mid X=x] P(X=x) = E[Y mid X=0] P(X=0) + E[Y mid X=1] P(X=1).$$






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Nice answer, angryavian.
    $endgroup$
    – callculus
    Jan 13 at 22:52
















1












$begingroup$

The conditional expectation of $Y$ given an event $A$ is
$$E[Y mid A] = frac{E[Y cdot 1_A]}{P(A)},$$
where $1_A$ is an indicator random variable that equals $1$ when the event $A$ occurs, and equals zero otherwise.



In your case you have $A = {X < 2}$.
The denominator is $P(A) = P(X=0) + P(X=1)$.
By the law of total expectation, the numerator is
$$E[Y cdot 1_A] = sum_{x=0}^2 E[Y cdot 1_A mid X=x] P(X=x) = E[Y mid X=0] P(X=0) + E[Y mid X=1] P(X=1).$$






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Nice answer, angryavian.
    $endgroup$
    – callculus
    Jan 13 at 22:52














1












1








1





$begingroup$

The conditional expectation of $Y$ given an event $A$ is
$$E[Y mid A] = frac{E[Y cdot 1_A]}{P(A)},$$
where $1_A$ is an indicator random variable that equals $1$ when the event $A$ occurs, and equals zero otherwise.



In your case you have $A = {X < 2}$.
The denominator is $P(A) = P(X=0) + P(X=1)$.
By the law of total expectation, the numerator is
$$E[Y cdot 1_A] = sum_{x=0}^2 E[Y cdot 1_A mid X=x] P(X=x) = E[Y mid X=0] P(X=0) + E[Y mid X=1] P(X=1).$$






share|cite|improve this answer









$endgroup$



The conditional expectation of $Y$ given an event $A$ is
$$E[Y mid A] = frac{E[Y cdot 1_A]}{P(A)},$$
where $1_A$ is an indicator random variable that equals $1$ when the event $A$ occurs, and equals zero otherwise.



In your case you have $A = {X < 2}$.
The denominator is $P(A) = P(X=0) + P(X=1)$.
By the law of total expectation, the numerator is
$$E[Y cdot 1_A] = sum_{x=0}^2 E[Y cdot 1_A mid X=x] P(X=x) = E[Y mid X=0] P(X=0) + E[Y mid X=1] P(X=1).$$







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Jan 13 at 22:28









angryavianangryavian

41.1k23380




41.1k23380












  • $begingroup$
    Nice answer, angryavian.
    $endgroup$
    – callculus
    Jan 13 at 22:52


















  • $begingroup$
    Nice answer, angryavian.
    $endgroup$
    – callculus
    Jan 13 at 22:52
















$begingroup$
Nice answer, angryavian.
$endgroup$
– callculus
Jan 13 at 22:52




$begingroup$
Nice answer, angryavian.
$endgroup$
– callculus
Jan 13 at 22:52


















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