Minimal number of points for a linear regression
Feb 10, 2023 · What would be a "reasonable" minimal number of observations to look for a trend over time with a linear regression? what about fitting a quadratic model? I work with composite indices of …
Linear regression, conditional expectations and expected values
Jun 25, 2016 · In the probability model underlying linear regression, X and Y are random variables. if so, as an example, if Y = obesity and X = age, if we take the conditional expectation E (Y|X=35) …
Assumptions of linear models and what to do if the residuals are not ...
For your first question, I don't think that a linear regression model assumes that your dependent and independent variables have to be normal. However, there is an assumption about the normality of …
regression - When is R squared negative? - Cross Validated
With linear regression with no constraints, R2 R 2 must be positive (or zero) and equals the square of the correlation coefficient, r r. A negative R2 R 2 is only possible with linear regression when either …
What happens when we introduce more variables to a linear regression …
Feb 22, 2020 · What happens when we introduce more variables to a linear regression model? Ask Question Asked 5 years, 9 months ago Modified 4 years, 7 months ago
How should outliers be dealt with in linear regression analysis?
Often times a statistical analyst is handed a set dataset and asked to fit a model using a technique such as linear regression. Very frequently the dataset is accompanied with a disclaimer similar...
Does it make sense to use a date variable in a regression?
I'm not used to using variables in the date format in R. I'm just wondering if it is possible to add a date variable as an explanatory variable in a linear regression model. If it's possible, how c...
In linear regression, when is it appropriate to use the log of an ...
Aug 24, 2021 · Taking logarithms allows these models to be estimated by linear regression. Good examples of this include the Cobb-Douglas production function in economics and the Mincer …
Using years when calculating linear regression? - Cross Validated
The assignment is to calculate the linear regression analysis/regression equation for a data set containing years and the percentage of unemployment in the population at that time.
regression - Interpreting the residuals vs. fitted values plot for ...
Therefore, the second and third plots, which seem to indicate dependency between the residuals and the fitted values, suggest a different model. But why does the second plot suggest, as Faraway …