Quick simulation of 50 experiments and their means and 95% confidence intervals

confidence_intervals.R

set.seed(1)
mu <- 0
sigma <- 1
N.trials <- 20
N.sims <- 50

rnorm(N.trials*N.sims, mu, sigma) |>
  matrix(nrow=N.sims) -> Y

d <- apply(Y, 1, \(y) c(mean(y), sd(y)/sqrt(length(y))))

plot(d[1,], pch=19, ylim=c(-1,1),
     col=ifelse(d[1,]+2*d[2,]<0 | d[1,]-2*d[2,]>0, "red", "black"),
     xlab="Simulation number", ylab="DV")
arrows(1:N.sims, d[1,]+2*d[2,], 1:N.sims, d[1,]-2*d[2,],
       col=ifelse(d[1,]+2*d[2,]<0 | d[1,]-2*d[2,]>0, "red", "black"),
       code=0, lwd=2)
abline(h=0, lty=2, col="red", lwd=3)