library("emmeans")


dat <- read.csv("ForEJ.csv", stringsAsFactors = TRUE)
dat <- dat[1:(nrow(dat)-1), ]

# Regression analysis
summary(lm(Like ~ Agree_Original_Coding * decision_condition, data = dat))
summary(lm(Like ~ I(Agree_Original_Coding-4) * decision_condition, data = dat))

# Comparable results within the original coding
original_lm <- lm(Like ~ Agree_Original_Coding * decision_condition, data = dat)
original_emm <- emmeans(original_lm, ~ Agree_Original_Coding * decision_condition, at = list(Agree_Original_Coding = 0))

pairs(original_emm)

original_emm <- emmeans(original_lm, ~ Agree_Original_Coding * decision_condition, at = list(Agree_Original_Coding = 4))

pairs(original_emm)


# Zero-sum coding
contrasts(dat$decision_condition) <- contr.sum(2) * 0.5

zero_sum_lm <- lm(Like ~ Agree_Original_Coding * decision_condition, data = dat)

summary(zero_sum_lm)

emtrends(original_lm, "decision_condition", var = "Agree_Original_Coding") |>
  contrast(list(a = c(0.5, 0.5))) |>
  summary(infer = TRUE)