library(psych)
library(granova)
library(Rcmdr)

#5. Obtain and view data
  anorexia=read.table("http://www.unt.edu/rss/class/mike/data/anorexia.txt", header=T)
  anorexia 

#6. Create 'change' variable, view new data set, attach data 
  anorexia$change=anorexia$Postwt-anorexia$Prewt  
  anorexia 
  attach(anorexia)

#8. Obtain descriptives
  describe.by(anorexia$change,Treat)

#9. Create histogram of 'change'
  hist(change)  

#10. Create boxplot
  plot(change~Treat)  

#11. Conduct ANOVA
  anovamod <- lm(change~Treat, data=anorexia)
  anova(anovamod)

#13. Diagnostic plots
  oldpar <- par(oma=c(0,0,3,0), mfrow=c(2,2))
  plot(anovamod)
  par(oldpar)

#14. Influence plot
  influencePlot(anovamod)

#15. Shapiro-Wilk test
  shapiro.test(anovamod$res)  

#16. Levene's test
  levene.test(change~Treat) 

#17. Plot ANOVA
  granova.1w(change,Treat, tr=T) 

#18. Welch F test
  oneway.test(change~Treat, data=anorexia)  

#19. Kruskal-Wallis test
  kruskal.test(change~Treat, data=anorexia)

#20. Welch F test with trimmed means
  source("http://www.unt.edu/rss/class/mike/Rallfun-v9_2.txt")  
  newanor=matrix(c(anorexia$Treat,anorexia$change), ncol=2)  
  modmod=t1way(newanor, MAT=T)  
  modmod

#21. Pairwise t-test using FDR to correct
  pairwise.t.test(change, Treat, p.adjust="fdr")