Linearity of phenomenon measured
The linearity of the dependent - independent variables relationship describes the degree change in the dependent variable as related to the independent variable .If the relationship between independent variables and the dependent variable is not linear, the results of the regression analysis will under -estimate the true relationship . A preferable method of detection is examination of residual plots (plots of standardized residuals as a function of standardized predicted values, readily available in most statistical software) is used to examine the linearity of any bivariate relationship. This research, all of the relationships between dependent and independent variable are linear. As a result, the linearity problems should not be concerned.c