Specifically set for statistics within psychology. Many of the methods used in here are being phased out, such as the manual calculations of t-tests and the inclusion and rejection of the null hypothesis. Still, a very easy guide to statistics.
Research Methods and Statistics by Sherri L. Jackson was a valuable resource during my time in grad school. While it may not be the most exciting read, it excels in making complex topics clear and understandable. Jackson's narrative style makes the material surprisingly easy to digest, which is a huge plus when tackling challenging subjects. Overall, a highly effective tool.