13.6 Is there an interaction? Each of the following tables gives means for a two-way ANOVA. Make a plot of the means with the levels of Factor A on the x axis. State whether or not there is an interaction, and if there is, describe it.

Factor A
Factor B 1 2 3
1 11 21 31
2 6 11 16
Factor A
Factor B 1 2 3
1 10 5 15
2 20 15 25
Factor A
Factor B 1 2 3
1 10 15 20
2 15 20 25
Factor A
Factor B 1 2 3
1 10 15 20
2 20 15 10