Question

A researcher wants to know if a new exercise program decreases total cholesterol. she knows that total cholesterol -n(170, 10). she collects a sample of 40 people and have them join the program for 2 weeks. after the two weeks, she collects their cholesterol and finds x = 155. if she uses a = .05, what is the probability of committing a type i error?

a. it depends on the = test statistic.
b. it is 15%.
c. it is 5%.
d. there is not enough information to answer this question.

Answer 1

The probability of committing a Type I error, given the significance level of 0.05, is 5%. The correct answer is option c, as it directly reflects the preset alpha level for the hypothesis test.

Step-by-step explanation:

The probability of committing a Type I error in hypothesis testing is denoted by alpha (α), which is the level of significance that the researcher sets before conducting the test. In this scenario, the researcher has set α = 0.05. This means that she is willing to accept a 5% chance of rejecting the true null hypothesis.

Therefore, the probability of committing a Type I error is directly equal to the significance level. Without needing to know the test statistic or additional information, we can answer the student's question.

So, the correct option for the probability of committing a Type I error is:

• c. it is 5%.