ABSTRACT
As discussed in the previous chapter, researchers use one-way ANOVA to investigate differences among three or more groups of individuals that vary on a dependent variable. However, sometimes there are other variables that could influence research results and that researchers have to take into account at the data analysis stage. In a pre-post study, such as Ko (2012), which was discussed in the previous chapter, it could have been the case that one of the groups had greater knowledge of the target feature at pretest time, so that any differences at posttest time might not have been due to the treatment alone. It is, therefore, important to be able to account statistically for differences that may exist before the treatment is applied. ANCOVA is one method that can be used for this purpose.
