Detect and address multicollinearity

Prompt

You fit a linear or logistic regression model and suspect multicollinearity among the predictors.

1. What is multicollinearity, and why does it create issues?
2. How would you detect it using specific diagnostics?
3. How would you address it with practical remedies?
4. After addressing it, what changes in interpretation or performance should you expect? Overview: This question tests knowledge of multicollinearity as a statistical concept plus the ability to recognize it, explain its impact on regression coefficients, and evaluate appropriate ways to mitigate it.