This paper describes how qualitative variables may be used in regression studies. A factorial model with convariates is assumed. The qualitative variables (factorial effects) are introduced into the ...

Using historical data and regression analysis has its limitations in business forecasting. For example, a significant correlation between the independent and dependent variable does not ...

Gary Chamberlain, Analysis of Covariance with Qualitative Data, The Review of Economic Studies, Vol. 47, No. 1, Econometrics Issue (Jan., 1980), pp. 225-238 ...

Design Systematic review, qualitative analysis and meta-analysis. Sorting of studies and quality assessments were performed by two independent authors. Qualitative analyses, relative risk (RR) ...