Type 1 hypothesis error

In a type one hypothesis error, we have a false positive - we state that we have sufficient evidence to reject the null hypothesis, but actually, the null hypothesis is still true.

Significance level

The higher the significance level, the more likely we are to have type 1 errors.

Probability of a type 1 error

The chance of having a type 1 error is equal to the calculated significance level - that is, the significance level we calculate when carrying out the hypothesis test (not the thing we’re testing for).