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re: Interpreting Coefficients in a Logistic Regression output: what is 1/e^ßX

Posted on 12/6/15 at 9:43 am to
Posted by steeltiger17
Member since Mar 2015
490 posts
Posted on 12/6/15 at 9:43 am to
quote:

it's better to try to keep up during the semester than wait til the end
manipulating the odds ratio is not required. This is a quest for more knowledge
Posted by NoFlexZone
Member since Sep 2015
429 posts
Posted on 12/6/15 at 9:49 am to
quote:

Go to library. Get book from Hosmer and Lemeshow. They are the kings.
What this guy said.

And I would add get Paul Allison - Logistic Regression using SAS. This book is the shite in understanding logistic regression with dichotomous data, ordinal data, or non-ordinal data. And you can analyse this with one covariate or several covariates.

The book only costs $49 on amazon.

Are you using R or SAS?
Posted by GeauxxxTigers23
TeamBunt General Manager
Member since Apr 2013
62514 posts
Posted on 12/6/15 at 9:50 am to
288
Posted by steeltiger17
Member since Mar 2015
490 posts
Posted on 12/6/15 at 9:54 am to
quote:

That variable is dichotomous
that is implied when I scored the cat variable as a 1 or 0. Lol
quote:

there is no '1 point increase' in such a variable.
that's nitpicking. Fine, one unit increase, since I would be adding new/unseen data to the model.
quote:

Why are you asking these questions? Don't you have a textbook?
textbook doesn't cover manipulating the odds ratio to better understand stat law. Why? BC I like to ask questions that are beyond what I need to know
Posted by steeltiger17
Member since Mar 2015
490 posts
Posted on 12/6/15 at 9:54 am to
quote:

is 1/e^ßX interpreting the odds ratio based on a "0" outcome of the target variable? while e^ßX is for "1" outcome? 


Yes
thank you good sir, BC this is actually correct
Posted by sullivanct19a
Florida
Member since Oct 2015
5239 posts
Posted on 12/6/15 at 9:58 am to
quote:

And I would add get Paul Allison - Logistic Regression using SAS.


Absolutely add this book.
Posted by sullivanct19a
Florida
Member since Oct 2015
5239 posts
Posted on 12/6/15 at 10:20 am to
quote:

steeltiger17


Yes, nitpicking, because it's clear you don't know what you're talking about. You're not going to realize that unless it's pointed out to you. That's all.
Posted by steeltiger17
Member since Mar 2015
490 posts
Posted on 12/6/15 at 10:39 am to
quote:

Yes, nitpicking,
dichotomous is a way to categorize a categorical variable. yea, that's nitpicking


1 point increase/ 1 unit increase when interpreting the coefficient is nit picking. that kind of nit picking is saved for a professor who takes off points just to do so. In the real world its understood what it means. sshiiit my professor does it all the time.
quote:

Each coefficient is evaluated in the context of holding all variables at their expected values.

understood by anyone understands regression models. does not needed to be said for someone who understands the question in the OP. unnecessary typing
quote:

because it's clear you don't know what you're talking about
lol
This post was edited on 12/6/15 at 11:48 am
Posted by ldts
Member since Aug 2015
2938 posts
Posted on 12/6/15 at 10:44 am to
quote:

Paul Allison - Logistic Regression using SAS


Another good one is Regression Models for Categorical Dependent Variables Using Stata by Long and Freese. It doesn't goes real in depth as far as theory, but is a good overview of the application of logit regression (among other types of models). Would make a good companion to something like the H&L text.
Posted by lsu480
Downtown Scottsdale
Member since Oct 2007
92903 posts
Posted on 12/6/15 at 10:46 am to
Damn you smart son!
Posted by LSURussian
Member since Feb 2005
135363 posts
Posted on 12/6/15 at 10:59 am to
Pi R squared.


No, Pi are round. Cornbread are square.
Posted by steeltiger17
Member since Mar 2015
490 posts
Posted on 12/6/15 at 11:32 am to
quote:

Another good one is Regression Models for Categorical Dependent Variables Using Stata by Long and Freese.
the first book i've seen that actually shows interpretation of an outcome not occurring in logistic regression and amazon had this section in the free sample. its done by using 1/e^ßX
This post was edited on 12/6/15 at 11:33 am
Posted by buckeye_vol
Member since Jul 2014
35406 posts
Posted on 12/6/15 at 8:46 pm to
quote:

That variable is dichotomous, not 'categorical',
It is still a categorical variable, just with one a binary, or dichotomous, outcome. The number of outcomes does not negate it's categorical status.
quote:

Each coefficient is evaluated in the context of holding all variables at their expected values.
And expand on this, the Beta coefficient refers to the change in the outcome variable based on a ONE unit change of that predictor variable, and as you said, all other variables are held constant.
Posted by go_tigres
Member since Sep 2013
5494 posts
Posted on 12/6/15 at 9:20 pm to
what did you say about my mother??
Posted by buckeye_vol
Member since Jul 2014
35406 posts
Posted on 12/6/15 at 9:32 pm to
quote:

the first book i've seen that actually shows interpretation of an outcome not occurring in logistic regression and amazon had this section in the free sample. its done by using 1/e^ßX
Just for clarification purposes, your output should have two Sets of results coefficients, one for the constant and one for Mobil. The constant is when Mobil is 0. Just want to make sure you're interpreting the Mobil variable and not the constant if you are talking about the 1 unit increase.

Anyways, if you're looking for other ways to interpret the coefficient, you can determine the probability of the outcome using the odds ratio as well. You may already know this though.

The simplest way is to take the OR/(1+ OR) but you can also get this answer using the beta coefficients, although that can get more complicated. 1/(1+e^-(ß0+b1x1) so if the X is 0 it is essentially 1/(1+e^-(ß0) or 1/(1+e^-(-1.5833)) = .174

Just FYI.
This post was edited on 12/6/15 at 9:56 pm
Posted by ladytiger118
Member since Aug 2009
20922 posts
Posted on 12/6/15 at 9:45 pm to
:wat:
Posted by soccerfüt
Location: A Series of Tubes
Member since May 2013
76192 posts
Posted on 12/6/15 at 9:59 pm to
Jesus God, don't you even Fournier Expression brah?

I hope your dental records are up to date.
Posted by sullivanct19a
Florida
Member since Oct 2015
5239 posts
Posted on 12/6/15 at 10:12 pm to
quote:

It is still a categorical variable, just with one a binary, or dichotomous, outcome. The number of outcomes does not negate it's categorical status.


True. But, there's a big difference in categories of color, and saying something is there or it's not. In reading his comments, it was clear he didn't understand that, which is why it needed to be pointed out.

Second part: Evaluate the conditional in the context of marginal expectations. Like how MIT economist Gruber worked to pass the ACA. He counted on the most representative state of the American voter - the moron.
Posted by NoFlexZone
Member since Sep 2015
429 posts
Posted on 12/7/15 at 12:49 pm to
quote:

don't you even Fournier Expression brah?
I almost took you seriously with this comment.

What do you know about Fourier Analysis?
Posted by Mullet Flap
Lysdexia
Member since Jun 2015
4208 posts
Posted on 12/7/15 at 12:51 pm to
Muskogee, Oklahoma
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