* for p < 0.05, ** for p < 0.01, etc.

The probability, assuming H₀ is true, of obtaining a test statistic at least as extreme as the one observed in the sample.

why we need to know the exact p-value?

because significance level α is for everyone.

• Scientific evidence strength exists on a continuum—not as a binary “yes/no”

So everyone should know some statistics. Including some Nobel awarders.

also people may mistake, which is the reason why, paper existed, for your scientific viewpoint.