R/oddsratioWald.proc.R

In wolass/anareg: Functions used in the analysis of the Anaphylaxis Registry

oddsratioWald.proc <- function(n00, n01, n10, n11, alpha = 0.05){
  #
  #  Compute the odds ratio between two binary variables, x and y,
  #  as defined by the four numbers nij:
  #
  #    n00 = number of cases where x = 0 and y = 0
  #    n01 = number of cases where x = 0 and y = 1
  #    n10 = number of cases where x = 1 and y = 0
  #    n11 = number of cases where x = 1 and y = 1
  #
  OR <- (n00 * n11)/(n01 * n10)
  #
  #  Compute the Wald confidence intervals:
  #
  siglog <- sqrt((1/n00) + (1/n01) + (1/n10) + (1/n11))
  zalph <- qnorm(1 - alpha/2)
  logOR <- log(OR)
  loglo <- logOR - zalph * siglog
  loghi <- logOR + zalph * siglog
  #
  ORlo <- exp(loglo)
  ORhi <- exp(loghi)
  #
  oframe <- data.frame(LowerCI = ORlo, OR = OR, UpperCI = ORhi, alpha = alpha)
  oframe
}