Time series regression usually involves independent variables other than a time-trend. However, the simple time-trend model is convenient for illustrating regression with autocorrelated errors, and ...

Regression with qualitative variables is different from analysis of variance and analysis of covariance. ... The dummy variable allows each firm type to have a different intercept and slope. The ...

Qualitative Variables. A two-valued qualitative variable can be represented by a single 0-or-1-valued "dummy" variable. If a qualitative variable has three or more possible values (e.g., make-of-car, ...

Francis L. Huang, Multilevel Modeling and Ordinary Least Squares Regression, The Journal of Experimental Education, Vol. 86, No. 2 (2018), ... may be biased when relevant higher-level variables are ...