A researcher is interested in the effect of a new class based on critical thinking. There is a population mean of = 20. The students in the class receive training and later receive the critical thinking test. The researcher wants to test the hypothesis that this new class affected the test scores.

1. State the null and alternative hypotheses (in words) as they relate to the research in this example:

2. State the null and alternative hypotheses (in symbols):

3. Define the alpha level and critical region for a hypothesis test:

4. Define a Type 1 and 2 error and explain consequences for each. Which one is worse and why?