7. Correct. The answer is false.

T=( b - b)*(n-2)²/(s_y.x/s_x)=(0.636-0.454)*6^0.5/(0.5641/4.062)=3.2095

Since s_y.x=0.5641 was computed in problem 8.4 and s_x=(`x<sup>2</sup>-(`x)²)^0.5=4.062 follows from problem 1.

On the basis of one-tailed t-test, we would reject the hypothesis that the regression coefficient is as low as 0.454 if t>t_0.95=1.94 for 8-2=6 degrees of freedom. Thus we reject the hypothesis.