Concept #1: Determining Critical Values and Rejection Regions

Concept #2: Determining Critical Values and Rejection Regions: Intro

Practice: The weight of all Lay’s chips produced should be 9.7 ounces per bag. A company will shut down a factory if they are producing bags which are weighing anything different than 9.7 ounces (lighter or heavier). A random sample of 16 bags is selected. The average and standard deviation from this sample is 9.8 and 2, respectively. If we want to test this using a 10% significance level, what would the rejection region be?

Practice: Referring to Practice 1, what would the rejection region be if we used an α = .05?

Practice: The average IQ of people within the United States is 100. It is believed that students who graduate from Harvard also have a higher IQ than the average American. 100 Harvard graduates are randomly selected and the mean and standard deviation are 125 and 20, respectively. What is the rejection region if you were to test the claim at an α = .001?

Practice: Referring to Practice 3, suppose we wanted to test to see if Garbage University had a lower IQ score than the average American. 64 Garbage graduates are randomly selected and the mean and standard deviation are 105 and 30, respectively. Using an α = .001, what would the rejection region be?