score_data <- data.frame(
section = rep(c("A", "B"), each = 4),
pretest = c(70, 75, 82, 78, 68, 74, 79, 81),
posttest = c(76, 79, 88, 83, 73, 80, 82, 87)
)
ai_summary <- score_data |>
dplyr::mutate(change = posttest - pretest) |>
dplyr::group_by(section) |>
dplyr::summarise(
mean_change = mean(change),
se_change = sd(change) / sqrt(nrow(score_data)),
.groups = "drop"
)
ai_summary# A tibble: 2 × 3
section mean_change se_change
<chr> <dbl> <dbl>
1 A 5.25 0.339
2 B 5 0.5
