Notes
The p-value is the probability, assuming $H_0$ is true, of getting a result at least as extreme as the one observed.
- Small p-value ($\le\alpha$): reject $H_0$; convincing evidence for $H_a$.
- Large p-value: fail to reject $H_0$.
Practice
p-value $=0.02$, $\alpha=0.05$:
$0.02<0.05$.
A p-value is calculated assuming:
It's a conditional probability under $H_0$.
A large p-value means:
We never prove $H_0$.
Ready for more? Take the Unit 3 test.