Question

fill in the blank
rejecting the null hypothesis when the null hypothesis is true is called
rejecting the null hypothesis when the null hypothesis is true is called
the significance level
power
a type ii error.
a type i error

Explanation:

In hypothesis testing, a Type I Error occurs when we wrongly reject a true null hypothesis. The significance level ($\alpha$) is the probability of making a Type I Error. Power is the probability of correctly rejecting a false null hypothesis. A Type II Error is failing to reject a false null hypothesis.

Answer:

a Type I Error