Abstract
This study focus to building a regression model without economic problems, the our model is focus on studying the time period for obtaining a degree of Ijtihad in religious sciences. The results showed through the variables involved in building The model under study, we find that there is a very large correlation between the explanatory variables, and thus this interference leads to the emergence of high correlations between the explanatory variables, and therefore the model will have a weak predictive efficiency, due to the exaggeration of the variance of the estimated parameters, and to overcome this problem a model was employed Regression Principal Components ..
