As the level of significance here is 0.05 because we are comparing the p-value with 0.05. Therefore the critical region boundaries here would be given as:
For 5 degrees of freedom, we get: ( from the t-distribution tables )
P(t_5 < 2.571) = 0.975
Therefore due to symmetry, we get:
P(-2.571 < t_5 < 2.571) = 0.95
Therefore the critical region here would be given as: +2.571 and -2.571