Use a z-test to test the hypothesis. What can you conclude from the result?

Task: A teacher has been teaching English for the past 10 terms. As a population, final exam scores are normally distributed with a mean of 62, and an SD(Standard Deviation) of 9. With the current class (i.e. sample) of n = 30 students, the teacher tries a different teaching format. Once a week, the class breaks down into smaller groups that meet with the teacher for discussion the reading material. At the end of the term, the teacher notes that the mean for this sample on the final exam was 66.5. Did the teaching format have a significant effect on performance on the final exam?
1. Identify the independent and dependent variables.
2. State an appropriate experimental hypothesis.
3. Does this require a one or two tailed test? Based on this, what is the critical value of z?
4. Use a z-test to test the hypothesis. What can you conclude from the result?