Excess return with T - Stat

Can some one let me know what the author is trying to do by comparing alpha with error -coefficient and the t-stats? Under what condition would we reject the null?


We would reject the null hypothesis if the absolute value of the t-statistic were greater than the t-critical value. Same as for any other 2-tail t-test.

Depending on the α you choose, the t-critical value could be around 1.6 or around 2.0 or above 2.0. In any case, 0.8 is not significant for any reasonable α.

Thank you for the reply.
Shouldn’t you reject the null if the T stats in higher than the critical value. As, higher t-stats means that the value is in the tail?(colored region)
One Tail test
What am I missing>

This is a 2-tail test: you can have positive excess return or negative excess return.