Perfect negative correlation (-1) between intercept and slope in a mixed model
27163
What to do with random effects correlation that equals 1 or -1?
12090
On Negative AIC Values
128388
Proper order of variables in unbalanced ANOVA
51310
Linear regression polynomial slope constraint in R
145044
Why do I get zero variance of a random effect in my mixed model, despite some variation in the data?
119496
Standardizing variables with negative values in R
52883
Correlation between OLS estimators for intercept and slope
111234
Interaction in generalized linear model
132450
What is wrong with the linear regression variance estimator when p+1>n?
138972
When is R squared negative?
107299
Working with systems with Perfect Multicollinearity
155671
How to show normalized cross correlation(NCC) lies in $[-1,1]$?
91668
Sign of Estimate (Coefficient) of Interaction Terms
71537
Interpreting a generalised linear mixed model with binomial data
13476
Fitting models in R where coefficients are subject to linear restriction(s)?
54795
Estimate error on slope of linear regression given data with associated uncertainty
130070
In linear regression, what does $\beta_1 = 0$ really mean?