Definition
If two or more covariates are highly correlated, in a multiple regression model, the model has a multicollinearity The multicollinearity makes the estimation of coefficient very unstable. So, the estimated coefficients are not reliable.
If two or more covariates are highly correlated, in a multiple regression model, the model has a multicollinearity The multicollinearity makes the estimation of coefficient very unstable. So, the estimated coefficients are not reliable.