I am reading the regression analysis resutls in a paper which showed most of the coefficients b2 and b3 are not significant but the R2 is significant. Eventhough there aren't too many variable in this model(see the model below), that happend. How come?
Is it still necessary to watch b2 and b3 and make conclusion like from b2 we can tell that there is a possitiv correlation between X and Y? The author did that but I am not sure whether one should do that if the coefficient is not significant at all.