R/Plot_Data_Correlation.R

In likanzhan/acqr: Functions Helping You understand Statistics Easily

#' @export
Create_Correlation_Data <- function(rr = 1, number = 50, nrm = TRUE) {
  if (nrm) {
    set.seed(2)
    df <- MASS::mvrnorm(
      n = number, mu = c(0, 0),
      Sigma = matrix(c(1, rr, rr, 1), ncol = 2),
      empirical = TRUE
    )
    df <- as.data.frame(df)
    colnames(df) <- c("X", "Y")
  } else {
    X <- seq(-3, 3, length.out = number)
    yfun <- function(x = X, a = 1, h = 0, k = 1) a * (x - h)^2 + k
    Y <- yfun(X)
    df <- data.frame(X = X, Y = Y)
  }
  return(df)
}

#' @export
Plot_Data_Correlation <- function(rr = 1, number = 50, nrm = TRUE) {
  df <- Create_Correlation_Data(rr = rr, number = number, nrm = nrm)
  rr <- cor(df[, "X"], df[, "Y"])
  rr <- round(rr, 3)
  plot(Y ~ X,
    data = df, pch = 19, col = "#cb2229",
    bty = "l", xaxt = "n", yaxt = "n",
    xlab = "", ylab = "", font.lab = 2
  )
  title(xlab = "X", ylab = "Y", line = 0)
  text(
    x = mean(range(df[, "X"])),
    y = max(df[, "Y"]),
    labels = bquote(r == .(rr))
  )
}