Type I Errors

My understanding was that the probability of a type I error is just the significance level of the hypothesis test? I just did a quick search online and found a few sources saying this. So I thought it would be 0.1 for the question below

But for this, they used the critical region (which is P(X<1) as calculated in part a) to work out P(type I error) ?

Nafisa is testing a 20-sided dice to see if the probability of rolling a one, p, is less than 0.05. She rolls the dice 100 times and records the number of ones scored, X. Nafisa models this using a binomial distribution, and decides to test at the 10% level of significance.

a) Find the critical region for Nasifa's test.
b) What is the probability of a Type I error in this test?

Yeah it won’t be exactly 0.1 since this is a discrete distribution.

Find the probability of falling into the critical region and that is it.

Thankyou - so if it was continuous it would be equal to the confidence interval?

Proposed significance level*, yes. Think about why.