Both box-and-whisker plot and bar chart are appropriate graphics for ANOVA according to The R Book (Crawley, 2013), but which is more appropriate? I suppose it depends on situation... can anybody help me?
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Specifically for graphical illustration of ANOVA:
Generally, there are many suggestions of which kinds of graphs are useful but little consensus about which are best. I'd suggest as criteria that a good graph shows
There are several designs that help with ANOVA, such as dot or strip plots with added means and SEs.
This paper by John Tukey explains the difference between propaganda graphs and analytical graphs that is pertinent here. Too many graphical illustrations of ANOVA are propaganda graphs (look! the groups are very different) without much analysis (and what else can we learn about the data or the limitations of the technique in this application?).
Please do not be confused between bar charts (one bar is used to show each quantity of interest) and dynamite plots (one bar shows the average of each group, plus error bars). Dynamite plots are NEVER acceptable because they hide the distribution of the data for no reason at all.
Yes I realize that this is by far the most common type of plot. It is a big problem that reflects the (low) importance that researchers place on the shape of their data. If you were a detective looking for a murder weapon, would it be better if a witness told you 1) only the location and size of the weapon? or 2) the location, size, and shape?