R code

plotNorm

# author: ljsa @ cin.ufpe.br

# sd = Standart deviation
# confidence = (0~1)
# Obj: ver se o estado esta dentro da area de confianca da media
plotNorm = function(mean, sd, confidence){
  curve (dnorm(x, mean, sd), xlim = c(mean - (3*sd), mean + (3*sd)));
  
  left = (1-confidence)/2;
  right = confidence + L;
  
  # funcao qnorm me retorna o ponto da normal de x
  dotL = qnorm(left, mean, sd);
  dotR = qnorm(right, mean, sd);
  interval = 0.01;
  
  cordX <- c(dotL, seq(dotL, dotR, interval), dotR);
  cordY <- c(0, dnorm(seq(dotL, dotR, interval), mean, sd), 0);
  
  polygon(cordX, cordY, col = "skyblue");
  polygon(c(mean, mean), c(0, dnorm(mean,mean,sd)), border="darkblue");
  
}