问题如下：
6. Is the relationship between the ratio of cash flow to operations and the ratio of net income to sales significant at the 5 percent level?
选项：
A. No, because the R-squared is greater than 0.05.
B. No, because the p-values of the intercept and slope are less than 0.05.
C. Yes, because the p-values for F and t for the slope coefficient are less than 0.05.
解释：
C is correct.
The p-value reflects the strength of the relationship between the two variables. In this case the p-value is less than 0.05, and thus the regression of the ratio of cash flow fromoperations to sales on the ratio of net income to sales is significant at the 5 percent level.
P value=0，怎么样都小于5%的1.96critical value啊，所以应该接受原假设，not significant啊，应该选B啊