问题如下：
An analyst tests the profitability of a trading strategy with the null hypothesis being that the average abnormal return before trading costs equals zero. The calculated t-statistic is 2.802, with critical values of ± 2.756 at significance level α = 0.01. After considering trading costs, the strategy’s return is near zero. The results are most likely:
选项：
A. statistically but not economically significant.
B. economically but not statistically significant.
C. neither statistically nor economically significant.
解释：
A is correct.
The hypothesis is a two-tailed formulation. The t-statistic of 2.802 falls outside the critical rejection points of less than –2.756 and greater than 2.756, therefore the null hypothesis is rejected; the result is statistically significant. However, despite the statistical results, trying to profit on the strategy is not likely to be economically meaningful because the return is near zero after transaction costs
最后一句话，考虑了trading cost后，return is near zero是个没用的条件，对吗？
