Convention for symbols indicating statistical significance?

Question

This question might probably also fit into Academia.SX. I'm writing my first paper in life sciences and I'm very often seeing asterisks as indicators for statistical significance (*).

I'm wondering if there's a convention on which symbol, and how many of them are to be used to indicate what the significance is, e.g. * for p < 0.05 and *** for p < 0.001?

Answer 1

Following is the convention:

ns      P > 0.05
*       P ≤ 0.05
**      P ≤ 0.01
***     P ≤ 0.001
****    P ≤ 0.0001

Answer 2

This is correct, but please don't fall in the trap of the star system: The Earth Is Round, p < .05 :-)

Answer 3

The convention is...

* yay, I can publish
** yay, I can publish and not get refuted
*** I have no idea what alpha means
**** my power is unfathomable
***** graphing the data and noting r = 0.98 wasn't good enough

Also, see the references in chi's answer.