# ANOVASoTL.R
# ANOVA for SoTL

#-----------------------------------------------------------------------------
# Import Data From Spreadsheet (Step 1)
df = read.table(file = "clipboard", sep = "\t", header = TRUE);
df; # if you did this right, you will see the students' data in the R console. 
#-----------------------------------------------------------------------------
# Boxplots of Data (Step 2)
boxplot(df$Test ~ df$Major,col = "cyan", 
        main = "Boxplots of students' test scores by major.");

boxplot(df$Test ~ df$Flavor,col = c("brown", "yellow"),
        main = "Boxplots of students' test scores by favorite flavor.");

boxplot(df$Test ~ df$Flavor*df$Major,col = "green",
        main = "Boxplots of students' test scores by major x favorite flavor.");
#-----------------------------------------------------------------------------
# Perform the ANOVA (Step 3)
dfANOVA <- aov(Test ~ Major * Flavor, data = df);
summary(dfANOVA);  
# you should see the ANOVA table in the R console.
#-----------------------------------------------------------------------------
# Make a table with means and standard deviations sd (Step 4)

# for main effects
agMajor = aggregate(Test~Major,  df, function(x) c(mean = mean(x), sd = sd(x),n = length(x)));
agMajor;

agFlavor = aggregate(Test~Flavor,  df, function(x) c(mean = mean(x), sd = sd(x), n = length(x)));
agFlavor ;

# for interaction effects
agMajorFlavor = aggregate(Test~Major*Flavor,  df, function(x) c(mean = mean(x), sd = sd(x),n = length(x)));
agMajorFlavor;
#-----------------------------------------------------------------------------
# End of script