Finding a logistic regression model which can achieve zero error on a training set training data for a binary...












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Not sure where to begin with this question, can anyone help out?



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    Is this from a book? If so can you share the title?
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    – grayQuant
    10 hours ago
















1












$begingroup$


Not sure where to begin with this question, can anyone help out?



enter image description here










share|cite|improve this question











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  • 1




    $begingroup$
    Is this from a book? If so can you share the title?
    $endgroup$
    – grayQuant
    10 hours ago














1












1








1


1



$begingroup$


Not sure where to begin with this question, can anyone help out?



enter image description here










share|cite|improve this question











$endgroup$




Not sure where to begin with this question, can anyone help out?



enter image description here







machine-learning self-study mathematical-statistics






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edited 12 hours ago









Bryan Krause

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697212










asked 12 hours ago







user239276















  • 1




    $begingroup$
    Is this from a book? If so can you share the title?
    $endgroup$
    – grayQuant
    10 hours ago














  • 1




    $begingroup$
    Is this from a book? If so can you share the title?
    $endgroup$
    – grayQuant
    10 hours ago








1




1




$begingroup$
Is this from a book? If so can you share the title?
$endgroup$
– grayQuant
10 hours ago




$begingroup$
Is this from a book? If so can you share the title?
$endgroup$
– grayQuant
10 hours ago










1 Answer
1






active

oldest

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13












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Logistic regression is a linear classifier, i.e. it draws a line (2D datasets) and classifies accordingly (one side is class 0, other side is class 1). So, if classes can be distinguished by a line (or hyperplane in higher dimensions), it is said that the dataset is linearly separable, though this dataset is not. One way to tackle this issue is creating new features, or applying transformations. For example, this dataset seems to be separable if you think radially, i.e. $R>alpha$, where $R$ is the radius, or distance to origin, which can be found by $R=sqrt{X_1^2+X_2^2}$. Constructing a logistic regression using this feature only, results in perfect classification.






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  • $begingroup$
    By log-reg, do you mean a logistic regression model? Thanks for your help by the way!
    $endgroup$
    – user239276
    12 hours ago












  • $begingroup$
    yes, sorry for ambiguity.
    $endgroup$
    – gunes
    12 hours ago






  • 1




    $begingroup$
    @gunes This might be a bit too much of an answer for a self-study question, although I don't typically police those here and am not certain where exactly the community falls on these sorts of questions besides what is included in the tag info.
    $endgroup$
    – Bryan Krause
    12 hours ago






  • 2




    $begingroup$
    (+1) It's worth noting that this is essentially using a very simple Radial Basis Network with logistic loss
    $endgroup$
    – Cliff AB
    11 hours ago








  • 1




    $begingroup$
    It may be worth noting that this will cause the logistic regression to not converge! The parameter estimate for R will tend to infinity!
    $endgroup$
    – Matthew Drury
    8 hours ago










protected by gung 2 hours ago



Thank you for your interest in this question.
Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).



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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









13












$begingroup$

Logistic regression is a linear classifier, i.e. it draws a line (2D datasets) and classifies accordingly (one side is class 0, other side is class 1). So, if classes can be distinguished by a line (or hyperplane in higher dimensions), it is said that the dataset is linearly separable, though this dataset is not. One way to tackle this issue is creating new features, or applying transformations. For example, this dataset seems to be separable if you think radially, i.e. $R>alpha$, where $R$ is the radius, or distance to origin, which can be found by $R=sqrt{X_1^2+X_2^2}$. Constructing a logistic regression using this feature only, results in perfect classification.






share|cite|improve this answer











$endgroup$













  • $begingroup$
    By log-reg, do you mean a logistic regression model? Thanks for your help by the way!
    $endgroup$
    – user239276
    12 hours ago












  • $begingroup$
    yes, sorry for ambiguity.
    $endgroup$
    – gunes
    12 hours ago






  • 1




    $begingroup$
    @gunes This might be a bit too much of an answer for a self-study question, although I don't typically police those here and am not certain where exactly the community falls on these sorts of questions besides what is included in the tag info.
    $endgroup$
    – Bryan Krause
    12 hours ago






  • 2




    $begingroup$
    (+1) It's worth noting that this is essentially using a very simple Radial Basis Network with logistic loss
    $endgroup$
    – Cliff AB
    11 hours ago








  • 1




    $begingroup$
    It may be worth noting that this will cause the logistic regression to not converge! The parameter estimate for R will tend to infinity!
    $endgroup$
    – Matthew Drury
    8 hours ago
















13












$begingroup$

Logistic regression is a linear classifier, i.e. it draws a line (2D datasets) and classifies accordingly (one side is class 0, other side is class 1). So, if classes can be distinguished by a line (or hyperplane in higher dimensions), it is said that the dataset is linearly separable, though this dataset is not. One way to tackle this issue is creating new features, or applying transformations. For example, this dataset seems to be separable if you think radially, i.e. $R>alpha$, where $R$ is the radius, or distance to origin, which can be found by $R=sqrt{X_1^2+X_2^2}$. Constructing a logistic regression using this feature only, results in perfect classification.






share|cite|improve this answer











$endgroup$













  • $begingroup$
    By log-reg, do you mean a logistic regression model? Thanks for your help by the way!
    $endgroup$
    – user239276
    12 hours ago












  • $begingroup$
    yes, sorry for ambiguity.
    $endgroup$
    – gunes
    12 hours ago






  • 1




    $begingroup$
    @gunes This might be a bit too much of an answer for a self-study question, although I don't typically police those here and am not certain where exactly the community falls on these sorts of questions besides what is included in the tag info.
    $endgroup$
    – Bryan Krause
    12 hours ago






  • 2




    $begingroup$
    (+1) It's worth noting that this is essentially using a very simple Radial Basis Network with logistic loss
    $endgroup$
    – Cliff AB
    11 hours ago








  • 1




    $begingroup$
    It may be worth noting that this will cause the logistic regression to not converge! The parameter estimate for R will tend to infinity!
    $endgroup$
    – Matthew Drury
    8 hours ago














13












13








13





$begingroup$

Logistic regression is a linear classifier, i.e. it draws a line (2D datasets) and classifies accordingly (one side is class 0, other side is class 1). So, if classes can be distinguished by a line (or hyperplane in higher dimensions), it is said that the dataset is linearly separable, though this dataset is not. One way to tackle this issue is creating new features, or applying transformations. For example, this dataset seems to be separable if you think radially, i.e. $R>alpha$, where $R$ is the radius, or distance to origin, which can be found by $R=sqrt{X_1^2+X_2^2}$. Constructing a logistic regression using this feature only, results in perfect classification.






share|cite|improve this answer











$endgroup$



Logistic regression is a linear classifier, i.e. it draws a line (2D datasets) and classifies accordingly (one side is class 0, other side is class 1). So, if classes can be distinguished by a line (or hyperplane in higher dimensions), it is said that the dataset is linearly separable, though this dataset is not. One way to tackle this issue is creating new features, or applying transformations. For example, this dataset seems to be separable if you think radially, i.e. $R>alpha$, where $R$ is the radius, or distance to origin, which can be found by $R=sqrt{X_1^2+X_2^2}$. Constructing a logistic regression using this feature only, results in perfect classification.







share|cite|improve this answer














share|cite|improve this answer



share|cite|improve this answer








edited 12 hours ago

























answered 12 hours ago









gunesgunes

5,4001115




5,4001115












  • $begingroup$
    By log-reg, do you mean a logistic regression model? Thanks for your help by the way!
    $endgroup$
    – user239276
    12 hours ago












  • $begingroup$
    yes, sorry for ambiguity.
    $endgroup$
    – gunes
    12 hours ago






  • 1




    $begingroup$
    @gunes This might be a bit too much of an answer for a self-study question, although I don't typically police those here and am not certain where exactly the community falls on these sorts of questions besides what is included in the tag info.
    $endgroup$
    – Bryan Krause
    12 hours ago






  • 2




    $begingroup$
    (+1) It's worth noting that this is essentially using a very simple Radial Basis Network with logistic loss
    $endgroup$
    – Cliff AB
    11 hours ago








  • 1




    $begingroup$
    It may be worth noting that this will cause the logistic regression to not converge! The parameter estimate for R will tend to infinity!
    $endgroup$
    – Matthew Drury
    8 hours ago


















  • $begingroup$
    By log-reg, do you mean a logistic regression model? Thanks for your help by the way!
    $endgroup$
    – user239276
    12 hours ago












  • $begingroup$
    yes, sorry for ambiguity.
    $endgroup$
    – gunes
    12 hours ago






  • 1




    $begingroup$
    @gunes This might be a bit too much of an answer for a self-study question, although I don't typically police those here and am not certain where exactly the community falls on these sorts of questions besides what is included in the tag info.
    $endgroup$
    – Bryan Krause
    12 hours ago






  • 2




    $begingroup$
    (+1) It's worth noting that this is essentially using a very simple Radial Basis Network with logistic loss
    $endgroup$
    – Cliff AB
    11 hours ago








  • 1




    $begingroup$
    It may be worth noting that this will cause the logistic regression to not converge! The parameter estimate for R will tend to infinity!
    $endgroup$
    – Matthew Drury
    8 hours ago
















$begingroup$
By log-reg, do you mean a logistic regression model? Thanks for your help by the way!
$endgroup$
– user239276
12 hours ago






$begingroup$
By log-reg, do you mean a logistic regression model? Thanks for your help by the way!
$endgroup$
– user239276
12 hours ago














$begingroup$
yes, sorry for ambiguity.
$endgroup$
– gunes
12 hours ago




$begingroup$
yes, sorry for ambiguity.
$endgroup$
– gunes
12 hours ago




1




1




$begingroup$
@gunes This might be a bit too much of an answer for a self-study question, although I don't typically police those here and am not certain where exactly the community falls on these sorts of questions besides what is included in the tag info.
$endgroup$
– Bryan Krause
12 hours ago




$begingroup$
@gunes This might be a bit too much of an answer for a self-study question, although I don't typically police those here and am not certain where exactly the community falls on these sorts of questions besides what is included in the tag info.
$endgroup$
– Bryan Krause
12 hours ago




2




2




$begingroup$
(+1) It's worth noting that this is essentially using a very simple Radial Basis Network with logistic loss
$endgroup$
– Cliff AB
11 hours ago






$begingroup$
(+1) It's worth noting that this is essentially using a very simple Radial Basis Network with logistic loss
$endgroup$
– Cliff AB
11 hours ago






1




1




$begingroup$
It may be worth noting that this will cause the logistic regression to not converge! The parameter estimate for R will tend to infinity!
$endgroup$
– Matthew Drury
8 hours ago




$begingroup$
It may be worth noting that this will cause the logistic regression to not converge! The parameter estimate for R will tend to infinity!
$endgroup$
– Matthew Drury
8 hours ago





protected by gung 2 hours ago



Thank you for your interest in this question.
Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).



Would you like to answer one of these unanswered questions instead?



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