If you already have a distribution and want to test the mean, the significance level is irrelevant. The Test Mean functionality shows everything you need (i.e. the entire distribution including the location of the hypothesized mean) and lets you open p-value as well as power animations.
![Ressel_0-1652871618620.png Ressel_0-1652871618620.png](https://community.jmp.com/t5/image/serverpage/image-id/42518iCD696B42D5AB594D/image-size/medium?v=v2&px=400)