Linked Questions

1 vote
1 answer
3k views

Are canonical link functions and link functions the same thing? [duplicate]

Are Canonical link functions and the link functions the same thing? If not, can anyone tell the difference between them? I know a link function is a function that links a linear predictor to the ...
User9523's user avatar
  • 605
0 votes
1 answer
94 views

GLM difference between the links [duplicate]

I'd be very grateful if someone could help me understand the idea behind link functions: I know that the idea is that we want to map the mean to the $\eta$-vector. Also, I know that the canonical ...
asdf's user avatar
  • 384
2 votes
0 answers
120 views

What makes the canonical link function special in GLMs? [duplicate]

Why is the canonical link function used so frequently with GLMs? What makes it "natural"? Is there any reason to think that, $Q(\theta _i)$ (where $Q$ is the canonical link function, and $\theta _i$ ...
dlaser's user avatar
  • 201
399 votes
12 answers
397k views

Difference between logit and probit models

What is the difference between Logit and Probit model? I'm more interested here in knowing when to use logistic regression, and when to use Probit. If there is any literature which defines it using ...
Beta's user avatar
  • 6,466
28 votes
3 answers
10k views

Intuition behind logistic regression

Recently I began studying machine learning, however I failed to grasp the intuition behind logistic regression. The following are the facts about logistic regression that I understand. As the basis ...
user16168's user avatar
  • 797
4 votes
4 answers
22k views

Fixed effect Logit with R

I would like to perform a Fixed effect logit estimation in R. Can someone point out a package that can do the job? Note: For the time being I'm not really interested in the random effect. Update; ...
DJJ's user avatar
  • 236
11 votes
3 answers
7k views

Problem understanding the logistic regression link function

I am trying to learn the logistic regression model. I came to know that there is no linear relationship between predictor variables and response variables since response variables are binary (...
Bibek Subedi's user avatar
8 votes
2 answers
11k views

Understand Link Function in Generalized Linear Model

I am still trying to learn (may be the terminology issue) what does "link function" mean. For example, in logistic regression, we assume response variable is coming form binomial distribution. The $\...
Haitao Du's user avatar
  • 37.3k
10 votes
2 answers
3k views

What useful properties does the canonical link function have?

So here I am studying generalized linear models. I know this question is quite naive and simple, but I do not exactly know why the link canonical function is so useful. Could someone provide me an ...
user avatar
5 votes
5 answers
895 views

Where does the binary logistic regression model equation come from?

In Frank Harrell's Regression Modeling Strategies, he states: The ordinary linear regression model is: $$C(Y|X)=E(Y|X)=X\beta$$ and given $X$, $Y$ has a normal distribution with mean $X\beta$ and ...
Dylan Russell's user avatar
8 votes
1 answer
25k views

Link function in a Gamma-distribution GLM

In a GLM, if the response variable has a Gamma distribution, why is the inverse used as the link function, i.e.: $\mu = -(X\beta)^{-1}$? In particular, why is the inverse the canonical link? Does it ...
user109168's user avatar
6 votes
2 answers
2k views

Two simple questions regarding GLM

I'm currently doing a modelling project. However, I haven't taken a bunch of statistics classes, so I have to teach myself generalized linear models. I'm reading Generalized Linear Models for ...
3x89g2's user avatar
  • 1,716
4 votes
1 answer
1k views

Is the link function in Probit model canonical?

If I understand correctly, Probit model is a generalized linear model. I didn't see it listed in the table, so I was wondering if its link function is canonical for some distribution?
Tim's user avatar
  • 19.8k
3 votes
2 answers
2k views

Why do we choose exponential function as the nonlinearity in Possion GLM

In Poisson GLM, the response variable $Y$ follows the Poisson distribution $$P(Y=y)=\lambda^y\exp(-\lambda)/y!$$ and: $$\lambda=\exp(\bf \theta^Tx)$$ My question is why do we use exponential as the ...
Cloudy's user avatar
  • 231
3 votes
0 answers
4k views

Why does the exponential distribution have a canonical link that can yield negative values?

The canonical link for the binomial is the logit. The linear predictor can be anything so it is usable for the probability after the logit transform is used. The case is analogous for the Poisson ...
Jan van den Broek's user avatar

15 30 50 per page