One topic that was good to review for me was the two-sided hypothesis testing for the mean with variance unknown. With the p-val being double sided, you need to look at the test stat and decide whether to use the lower or upper tail. The smaller tail must be doubled to find an accurate p-val. If the wrong tail is used that will skew the p-val and will possibly provide the wrong conclusion of the test. This review was a good use of the class to refresh what I learned last semester!