Final answer:
The probability of a Type I error is 0.05.
Step-by-step explanation:
The probability of a Type I error, denoted by alpha (α), is the probability of rejecting the null hypothesis when it is actually true. In this case, the researcher set alpha to be 0.05, which means that there is a 5% chance of making a Type I error.
Therefore, the answer to the question is 3) .05.