# ferdo R Lab - Ders 2 - setup checks (base R, no extra packages)
path <- "data/class_synthetic.csv"
stopifnot(file.exists(path))
d <- read.csv(path, na.strings=c("","NA"), stringsAsFactors=FALSE)
stopifnot(nrow(d)==12L, ncol(d)==4L,
          length(unique(d$student_id))==12L,
          sum(is.na(d$study_hours))==1L,
          sum(is.na(d$quiz_score))==1L,
          sum(complete.cases(d[,c("study_hours","quiz_score")]))==10L,
          all(d$group %in% c("A","B")),
          isTRUE(all.equal(mean(d$quiz_score,na.rm=TRUE),718/11)))
cat("R LAB LESSON 2 SETUP CHECK PASS\n")