# ferdo R Lab | Lesson 6 | Warm-up (not a solution)
stopifnot(file.exists("data/class_synthetic.csv"))
d <- read.csv("data/class_synthetic.csv",na.strings=c("","NA"),
              stringsAsFactors=FALSE)
d$group <- factor(d$group,levels=c("A","B"))
cat("Dataset dimensions:",paste(dim(d),collapse=" x "),"\n")
print(names(d)); print(head(d,3))
score_known <- !is.na(d$quiz_score)
cat("Available quiz scores:",sum(score_known),"\n")
hist(d$quiz_score[score_known],breaks=seq(40,100,by=10),
     right=FALSE,main="Fictional quiz scores",xlab="Quiz score",
     ylab="Observed frequency")
# Students: design and label TWO independent plots in analysis_starter.R