update ws04 :uk: :fr:

[willvieira]

• Remove second empty slide
• Slide 3, 6 et 7: fix equation typo
• Slide 12: remove quantitative in the french version
• Slide 13, 18, 19, 62: typo
• Slide 15, 45: fix font size
Slide 20, 40, 54, 62, 75: improve layout
• Slide 25, 26, 33, 34, 38, 39, 44, 46, 70, 71, 72, 107, 109: Adj fig size
• Slide 41: fix code typo (lm2$coef -> lm2$coefficients)
• Slide 47: Add code to plot figure
• Slide 51: split in two slides and add a conceptual figure for Anova (R script in the script folder)
• Slide 52: split in two slides
• Slide 61: fix code typo (anova(ttest.lm1)$F -> anova(ttest.lm1)$F value)
• Slide 76: missing words
• Slide 84: Remove slide header so the code can fit on it
• Slide 86: add that it is not necessary to analyze interactions (parsimony)