# Statistics Lab / ferdo — synthetic data (no real student records)
# Save stats_synthetic.csv in your working directory.
d <- read.csv("stats_synthetic.csv", stringsAsFactors = TRUE)
stopifnot(nrow(d) == 36, all(c("score_pre","score_post","group") %in% names(d)))
# Groups are observational labels: differences cannot establish a treatment effect.

# Capstone starter: edit the research question and planned analysis.
stopifnot(nrow(d)==36)
summary(d$score_post)
table(d$group)
plot(d$study_hours, d$score_post, pch=19,
     xlab="Study hours", ylab="Post score")
boxplot(score_post ~ group, data=d, ylab="Post score")
cor.test(d$study_hours, d$score_post)
# Write interpretation, uncertainty, and limitations in your report.