The following two models have been estimated to investigate the determinants of leverage with a sample size of 80 firms. Residual sum of squares (RSS) of the restricted and unrestricted models are provided next to their corresponding equations below. Leverage = + 1(Tangibility) + 2(Profitability) + 3(Growth) + e RSS=200 Leverage = + 1(Tangibility) + e RSS=320

Test the joint significance of (Profitability) and (Growth) at the 5% significance level and interpret whether (Profitability) and (Growth) should remain in the model (the critical F value is 3.11).