Now that we’ve covered the 68-95-99.7% rule in tutorial 10, the next logical topic is Z scores (sometimes called standard scores or standardised scores). There’s a simple formula for working these out once you know what you’re doing. So this tute is pretty brief but covers all you need to know about Z scores. It [...]

Summary statistics is a fairly big and rather important topic, so I’ve split this into four videos. Part 1 explains mean and mode, part 2 looks at calculating the median, part 3 covers range and interquartile range (IQR) and part four shows you how to calculate standard deviation and variance. [Update - I've put another [...]