How to deal with variables that are only relevant for some people?
2219
How do you deal with "nested" variables in a regression model?
92702
Absolute variable as dependent variable
1208
How to test multiple variables against a single value?
27312
How can I account for a nonlinear variable in a logistic regression?
54879
Using x to predict y when they are highly correlated
54719
How to handle equality constraints in this problem?
30387
How exactly does one “control for other variables”?
142573
Replacing composite variables by a single variable
126848
How do I target players with only a certain X, Y, or Z coordinate?
56503
Theil-Sen estimation, more than one independent variable
119340
correlation with ordinal variable
55662
How to use principal components analysis to select variables for regression?
6089
Can I ignore coefficients for non-significant levels of factors in a linear model?
102203
Elegant manipulation of the variables list
45291
Overmatching bias and confounding variables
148679
Modelling with more variables than data points
13863
Is it advisable to drop certain levels of a categorical variable?