SAS Courses Online | Analysis of Variance (ANOVA) explained with example

you set up an experiment with three groups of people. The first group gets water to drink. The second group gets some sugary fruit juice and the third group gets coffee. Now you test everyone’s reaction time. Myself wants to know if there’s any difference in reaction time between the groups. The null hypothesis says that the mean reaction time for all three groups is the same. If there were only two groups, you could use a T test to find out if there’s a difference between them. But when you have three groups or more, you need to use a different approach, the analysis of variance. When you do the experiment, the scores won’t all be the same. The total variation of all the scores is made-up of two parts, the variation within each group because the people in each group have different reaction times. And the variation between the groups because the drinks you gave each group are different. Here’s an example. Look at this set of scores. They’ve been sorted into order to make it easier to s...