Linked Questions

2 votes
0 answers
943 views

Polynomial regression multicollinearity assumption? [duplicate]

The difference between Linear regression and Polynomial regression is that in the last we manipulate our original explanatory ...
Carlos Muradyan's user avatar
1 vote
2 answers
438 views

Conflicting p-values of regressors in simple regression vs multiple regression? [duplicate]

Consider the results of the following code. ...
ManUtdBloke's user avatar
0 votes
0 answers
290 views

Why, intuitively, does redundancy in a multiple linear regression increase the standard error of the partial regression coefficients? [duplicate]

In his book "Applied Multiple Regression/Correlation Analysis for the Behavioral Sciences", J. Cohen says that redundancy in the independent variables of a multiple regression model increases the ...
AlphaOmega's user avatar
1 vote
0 answers
72 views

Dissertation Results. X and Y non-correlation, but then X significantly predictive in regression model. Why? [duplicate]

I just finished my dissertation results and trying to interpret them and very confused. Basically, X and Y are not correlated but then when I put X in my regression model with a few other variables X ...
Kay's user avatar
  • 11
0 votes
0 answers
27 views

Why are the standard errors of these two outputs so different? [duplicate]

Context of the question: Two professors want to look at the effect of students’ high school math marks on their marks in their first calculus course. All marks are between 0 and 100. Using data from ...
Phlorpy's user avatar
73 votes
2 answers
27k views

Is there a difference between 'controlling for' and 'ignoring' other variables in multiple regression?

The coefficient of an explanatory variable in a multiple regression tells us the relationship of that explanatory variable with the dependent variable. All this, while 'controlling' for the other ...
Siddharth Gopi's user avatar
50 votes
4 answers
61k views

How to interpret coefficients from a polynomial model fit?

I'm trying to create a second order polynomial fit to some data I have. Let's say I plot this fit with ggplot(): ...
user13907's user avatar
  • 697
22 votes
3 answers
56k views

When can we speak of collinearity

In linear models we need to check if a relationship exists among the explanatory variables. If they correlate too much then there is collinearity (i.e., the variables partly explain each other). I am ...
Stefan's user avatar
  • 805
9 votes
2 answers
2k views

Does introduction of new variable always increase the p-val of existing ones?

I am doing some work that requires some estimates of gasoline oil demand elasticity on certain countries. After doing various econometric measures such as instrumental variable, I was able to get ...
The One's user avatar
  • 235
3 votes
3 answers
4k views

Visualising uncertainty in slope and offset for a regression line?

According to a least squares fit I have performed to my data, my slope is $-0.1038±0.033$, and my offset $0.1065±0.032$. My first idea was to visualise this by drawing three lines: $0.1065-0.1038x$, $...
gerrit's user avatar
  • 1,439
81 votes
0 answers
64k views

How can a regression be significant yet all predictors be non-significant? [duplicate]

My multiple regression analysis model has a statistically significant F value however all beta values are statistically non-significant. All the regression assumptions are met. No multicollinearity ...
Serene's user avatar
  • 811
3 votes
3 answers
4k views

Correlations between explanatory variables in regression

I'm just starting to learn about linear regression models and time series analysis and came upon the following doubt. Suppose we have a variable $Y$ that we're trying to model using $p$ explanatory ...
Spine Feast's user avatar
3 votes
3 answers
2k views

Modelling explanatory variables which depend on each other

I'm trying to estimate the value of an apartment, by doing a regression through similar apartments. The regression model looks now like this ...
Paul's user avatar
  • 471
1 vote
1 answer
3k views

Effect of combining predictor variables in a regression model

Let's say I first run a linear regression model Sales = f(TV Spend, Digital Spend). Now I add TV Spend and Digital Spend and run the second model. My second model is Sales = f(TV Spend+Digital Spend)...
Sharath G's user avatar
5 votes
1 answer
433 views

Why one result is so wide in this logistic multiple regession

I am doing multiple logistic regression with data with 24 predictor variables and 193 rows. All predictor variables have values of 0 or 1 and outcome variables (OUTVAR) also has only 2 possibilities. ...
rnso's user avatar
  • 10.2k

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