r - 在 R 中绘制具有绝对值的分布图

Question

z 分数是 $|Z| > 2$ 和代码如下所示。分布图是空白的，没有显示下限和上限。

mu1 = 0
sigma1 = 1
z.lbscore_d <- abs(2)
z.ubscore_d <- abs(2)

# Draw the normal distribution
range.d = seq(mu1-5*sigma1, mu1 + 5*sigma1, 0.01) 
y.d = dnorm(range.d, mu1, sigma1)
plot(range.d, y.d, type='l', ylim=c(0,max(y.d)+0.01), axes = FALSE)
axis(1, at = seq(mu1-5*sigma1, mu1 + 5*sigma1,sigma1))

# Add area to the middle
d <- range.d > z.lbscore_d & range.d < z.ubscore_d
lines(range.d, y.d)
polygon(z.lbscore_d, range.d[d], z.ubscore_d), c(0, y.d[d], 0), col = "red")

area <- pnorm(z.ubscore_d, mu1, sigma1) - pnorm(z.lbscore_d, mu1, sigma1)
result <- paste("P(", z.lbscore_d, "< IQ <", z.ubscore_d,") =", signif(area, digits = 4))
mtext(result, 5)

标签： rstatistics