The standard deviation is the most common measure of variability. It’s less intuitive than measures of central tendency such as the mean, but it plays an essential role in analysis and sample size planning. The standard deviation is a key ingredient when building a confidence interval and can be easily computed from a sample of
Driving down the road while only looking in the rearview mirror … that gives you a good idea of where you’ve been, but unless the road behind you is exactly like the one in front of you, you may run into some obstacles, to put it mildly. Safe and effective driving means looking forward and
UX research and UX measurement can be seen as an extension of experimental design. At the heart of experimental design lie variables. Earlier we wrote about different kinds of variables. In short, dependent variables are what you get (outcomes), independent variables are what you set, and extraneous variables are what you can’t forget (to account
