Linked Questions

1
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1answer
428 views

Should a non-significant adjustment variable be kept in a regression model? [duplicate]

I'm working with a structural equation model to study influenza infection risk. As age is a known risk factor to explain infection, I therefore adjusted my infection outcome on the subjects age class. ...
0
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2answers
224 views

How to interpret logistic regression output? [duplicate]

I have the R output for the logistic regression model. It seems that only the intercept and psa are statistically significant. Does that mean I should remove sorbets_psa and cinko from my model and ...
1
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0answers
131 views

Removing insignificant variables? [duplicate]

Suppose you fit a linear regression model on some data with 10 variables. The F-statistic shows that 3 of them are significant (p < 0.05) , 2 are within trend (0.05 < p < 0.10), and the other ...
11
votes
2answers
65k views

What is the difference between “factors” and “covariate” in terms of ANCOVA? [duplicate]

I am a bit confused on the term "covariate". It seems like the term can mean two different things. In ANCOVA, the term is used for the third variable that is not directly related to the experiment. ...
3
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4answers
10k views

How to identify which features are more likely to contribute to the desired outcome?

This question is in tandem with my earlier question here: Using ML approaches to build a recommender engine for sales team However, now I'd like to discover insights about x features as ...
5
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1answer
2k views

When is it better to use Multiple Linear Regression instead of Polynomial Regression?

In the course I've just learnt Multiple Linear Regression and Polynomial Regression. Why would you ever use Multiple Linear Regression when Polynomial Regression will always fit the data better?
2
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1answer
14k views

How to interpret non-significant effect of a covariate in ANCOVA?

I need to use ANCOVA to analyse effect of executive functions (EF-covariate) on scores collected during a test. I want to compare this effect between a control and schizophrenics group (variable ...
0
votes
2answers
2k views

How to remove one of the factor from the model?

We have a variable "pos" in the regression which has three values : guard, forward, and center. My regression looks like y~a+factor(pos) But one of the factor's value is insignificant (i.e. forward). ...
3
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1answer
15k views

Regression - What to do with insignificant variables?

Please pardon me if you find this question very silly but this doubt has been troubling me for some time now whenever I want to run a regression. I am working on SAS. I have a dataset which has 24,...
1
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1answer
2k views

what to do if all control variables are insignificant and none affect the main effects?

All the control variables were there because they affected the dependent variables in previous studies. However in my dataset, all are insignificant and do not affect the main effects. Should I ...
1
vote
1answer
4k views

Are insignificant variables included in calculation of predicted probabilities?

When calculating the predicted probabilities in a logistic regression model, do we consider all the variables or just the significant ones? For eg: Let's say my model has: dependent variable Y and 3 ...
1
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1answer
2k views

Help writing covariates into regression formula

Can someone take a shot at writing a formula using covariates into a linear regression formula? I need some feedback to see if I am on the right track. Much appreciated! Here are my basic ...
6
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1answer
204 views

Is there a counterexample to the claim that throwing away “insignificant” predictors doesn't generally harm a model?

I have learned from this site (see question here), and from Frank Harrell's Regression Modeling Strategies that generally speaking one should not remove variables because they are insignificant. I was ...
4
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1answer
177 views

Model selection, issues of judgement

I have a general question on model selection strategies in regression models. In my research, the main goal is rarely prediction but almost always estimation of effects of certain variables. I have ...
0
votes
1answer
717 views

ROC analysis and death/recurrence as binary marker

I am doing ROC-curve analysis on my patient cohort, and I am wondering if it is statistically ok to use "death" and "recurrence" as the binary marker, even though these parameters will be influenced ...

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