Answer
See below.
Work Step by Step
$x$ has a normal distribution, so the sampling distribution of the sample mean $\overline{x} $ is also normal. The sampling distribution of the sample mean has a mean $μ=0$ and a standard deviation of $\sigma_{\overline{x}}=\frac{\sigma}{\sqrt n}=\frac{60}{\sqrt{18}}\approx14.142$,