Hypothesis Testing - Interpretation of significance level?

[johnvedro72]

A Level - Edexcel Statistics Year 2 - Hypothesis testing for zero correlation

Question:



Solution:


Can someone explain why the significance level is the probability that the null hypothesis is true?
Is the significance level always the probability that the null hypothesis is true? Or is this contextual, and why?

Haven't exactly been taught all specific details like what significance level is; just been taught a numberline and critical region method for approaching hypothesis tests. Googling this hurts my brain, please make your answer detailed but understandable for a newbie like myself.

Thanks!

 

[Harry_the_cat]

In general, the significance level, also denoted as alpha or α, is the probability of rejecting the null hypothesis when it is true.

In your context above, the null hypothesis HAS been rejected (see part c), so you are saying that the null hypothesis is not true (but the prob that it is true is 0.05.)