LFD Book Forum Noisy Target vs Target Distribution,Deterministic Target vs Deterministic Target Func
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#1
01-25-2016, 09:10 PM
 ntvy95 Member Join Date: Jan 2016 Posts: 37
Noisy Target vs Target Distribution,Deterministic Target vs Deterministic Target Func

Hello, I am confused by the meaning of these four words:

Noisy Target vs Target Distribution

I understand that a target distribution is a probability distribution, but how about noisy target? What is a noisy target? A value or a function or a probability distribution?

Deterministic Target vs Deterministic Target Function

Same above, I understand that a deterministic target function is a function, but how about deterministic target? A value or a function?

And...

Quote:
 Noisy target = deterministic target f(x) = E(y|x) plus noise y − f(x)
Is y here a value or a function?

I am very confused...

Thank you very much for your time spending on here.
#2
01-27-2016, 07:52 AM
 magdon RPI Join Date: Aug 2009 Location: Troy, NY, USA. Posts: 597
Re: Noisy Target vs Target Distribution,Deterministic Target vs Deterministic Target

Apologies for the confusion.

Noisy target and deterministic target refer to a specific target value (for example at a specific point x). So you have a data point (x,y).

If y=f(x), we say that y is a deterministic target and f is a deterministic target function.

If for the same value of x you may observe different values of y (the example in the book: several people may have the same income but some may default on credit debt and some may not), then we say that y is a noisy target - its value is not deterministically determined given x. The way we model this situation is using a target distribution P[y|x]. So P[y|x] is the distribution of the (noisy) target, and we call it the target distribution.

Hope this helps.

Quote:
 Originally Posted by ntvy95 Hello, I am confused by the meaning of these four words: Noisy Target vs Target Distribution I understand that a target distribution is a probability distribution, but how about noisy target? What is a noisy target? A value or a function or a probability distribution? Deterministic Target vs Deterministic Target Function Same above, I understand that a deterministic target function is a function, but how about deterministic target? A value or a function? And... Is y here a value or a function? I am very confused... Thank you very much for your time spending on here.
__________________
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#3
01-29-2016, 06:30 AM
 ntvy95 Member Join Date: Jan 2016 Posts: 37
Re: Noisy Target vs Target Distribution,Deterministic Target vs Deterministic Target

Quote:
 Originally Posted by magdon Apologies for the confusion. Noisy target and deterministic target refer to a specific target value (for example at a specific point x). So you have a data point (x,y). If y=f(x), we say that y is a deterministic target and f is a deterministic target function. If for the same value of x you may observe different values of y (the example in the book: several people may have the same income but some may default on credit debt and some may not), then we say that y is a noisy target - its value is not deterministically determined given x. The way we model this situation is using a target distribution P[y|x]. So P[y|x] is the distribution of the (noisy) target, and we call it the target distribution. Hope this helps.
So y here serves as a (random) variable?
#4
02-09-2016, 08:28 AM
 MaciekLeks Member Join Date: Jan 2016 Location: Katowice, Upper Silesia, Poland Posts: 17
Re: Noisy Target vs Target Distribution,Deterministic Target vs Deterministic Target

Quote:
 Originally Posted by ntvy95 So y here serves as a (random) variable?
As the book says: "Instead of y=f(x), we can take the output y to be a random variable..."
#5
02-09-2016, 09:00 AM
 ntvy95 Member Join Date: Jan 2016 Posts: 37
Re: Noisy Target vs Target Distribution,Deterministic Target vs Deterministic Target

Quote:
 Originally Posted by MaciekLeks As the book says: "Instead of y=f(x), we can take the output y to be a random variable..."
Man, thank you. I have missed that important point. :'(

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