Answer
$T\gt T_\frac{α}{2}$: null hypothesis is not rejected.
There is not enough evidence to conclude that $M\ne0$.
Work Step by Step
Two-tailed test.
$|T_-|\lt T_+$. So:
Test statistic: $T=|T_-|=45$
Critical value: $T_\frac{α}{2}=21$
(According to table XII, for $n=14$ and $\frac{α}{2}=0.025$)
Since $T\gt T_\frac{α}{2}$, we do not reject the null hypothesis.
