Figure 1

Test for normality by Shapiro-Wilk statistic for residual obtained from 3 × 4 ANOVA with response variable being non-transformed (red), power transformed without treatment effect (blue), and power transformed with treatment effect and their interaction (green). The horizontal dot line represents 5% significant level. All box plots are obtained from 30 datasets selected at random from 1000 simulation (for clarity) with whiskers representing the 10^th and 90^th percentiles.