R_dnorm_dt
こんなコードを紹介した。
x <- 1:20 curve(dnorm, -4, 4, col = 2, lty = 2, lwd = 2) my.dt <- function(x) dt(x, 19) curve(my.dt, -4, 4, add = T, col = 5, lty= 3, lwd = 2) legend(-4, .4, legend= c("正規分布", "t分布"), col = c(2,5), lty = c(2,3), lwd = 2)
R_正規分布のプロット図もみてください。
par(mfrow = c(2,2)) ######### my.mean <- 50 my.sd <- 10 my.dnorm <- function(x) dnorm(x, mean = my.mean, sd = my.sd) plot(my.dnorm, 20, 80, main = paste("平均=", my.mean , "標準偏差= ", my.sd, " の正規分布",sep = ""),ylab = "頻度", xlab = "平均") xvals <- seq(my.mean - my.sd * 2, my.mean + my.sd * 2, length = 100) dvals <- my.dnorm(xvals) polygon(c(xvals, rev(xvals) ) , c(rep(0, 100), rev(dvals)), col = "yellow") text(my.mean, my.dnorm(my.mean) , lab = "95%", cex = 1.8) text(my.mean - my.sd * 2.1, my.dnorm(my.mean - my.sd * 2) , lab = "2.5%", cex = 1.2, col = "red") text(my.mean + my.sd * 2.1, my.dnorm(my.mean + my.sd * 2) , lab = "2.5%", cex = 1.2, col = "red") lines(c(my.mean - my.sd * 2, my.mean + my.sd * 2 ), c(0,0)) lines(c(my.mean,my.mean), c(0,my.dnorm(my.mean)), lty=2, col ="blue", lwd = 3) #########
######### my.mean <- 175 my.sd <- 8.8 my.dnorm <- function(x) dnorm(x, mean = my.mean, sd = my.sd) plot(my.dnorm, my.mean - my.sd * 3, my.mean + my.sd * 3, main = paste("平均=", my.mean , 標準偏差=", my.sd, " の正規分布",sep = ""),ylab = "頻度", xlab = "平均") xvals <- seq(my.mean - my.sd * 2, my.mean + my.sd * 2, length = 100) dvals <- my.dnorm(xvals) polygon(c(xvals, rev(xvals) ) , c(rep(0, 100), rev(dvals)), col = "yellow") text(my.mean, my.dnorm(my.mean) , lab = "95%", cex = 1.8) text(my.mean - my.sd * 2.1, my.dnorm(my.mean - my.sd * 2) , lab = "2.5%", cex = 1.2, col = "red") text(my.mean + my.sd * 2.1, my.dnorm(my.mean + my.sd * 2) , lab = "2.5%", cex = 1.2, col = "red") lines(c(my.mean - my.sd * 2, my.mean + my.sd * 2 ), c(0,0)) lines(c(my.mean,my.mean), c(0,my.dnorm(my.mean)), lty=2, col ="blue", lwd = 3) #########
### legend(-4.5, .4, legend= c("平均を中心に左右に標準偏差2個")) ######### my.mean <- 7 my.sd <- 2 my.dnorm <- function(x) dnorm(x, mean = my.mean, sd = my.sd) plot(my.dnorm, my.mean - my.sd * 3, my.mean + my.sd * 3, main = paste("平均=", my.mean , ", 標準偏差=", my.sd, " の正規分布",sep = ""),ylab = "頻度", xlab = "平均") xvals <- seq(my.mean - my.sd * 2, my.mean + my.sd * 2, length = 100) dvals <- my.dnorm(xvals) polygon(c(xvals, rev(xvals) ) , c(rep(0, 100), rev(dvals)), col = "yellow") text(my.mean, my.dnorm(my.mean) , lab = "95%", cex = 1.8) text(my.mean - my.sd * 2.1, my.dnorm(my.mean - my.sd * 2), lab = "2.5%", cex = 1.2, col = "red") text(my.mean + my.sd * 2.1, my.dnorm(my.mean + my.sd * 2) , lab = "2.5%", cex = 1.2, col = "red") lines(c(my.mean - my.sd * 2, my.mean + my.sd * 2 ), c(0,0)) lines(c(my.mean,my.mean), c(0,my.dnorm(my.mean)), lty=2, col ="blue", lwd = 3) #########
######### my.mean <- 0 my.sd <- 1 my.dnorm <- function(x) dnorm(x, mean = my.mean, sd = my.sd) plot(my.dnorm, my.mean - my.sd * 3, my.mean + my.sd * 3, main = paste("平均=", my.mean , ", 標準偏差=", my.sd, " の正規分布",sep = ""),ylab = "頻度", xlab = "平均") xvals <- seq(my.mean - my.sd * 2, my.mean + my.sd * 2, length = 100) dvals <- my.dnorm(xvals) polygon(c(xvals, rev(xvals) ) , c(rep(0, 100), rev(dvals)), col = "yellow") text(my.mean, my.dnorm(my.mean) , lab = "95%", cex = 1.8) text(my.mean - my.sd * 2.1, my.dnorm(my.mean - my.sd * 2), lab = "2.5%", cex = 1.2, col = "red") text(my.mean + my.sd * 2.1, my.dnorm(my.mean + my.sd * 2), lab = "2.5%", cex = 1.2, col = "red") lines(c(my.mean - my.sd * 2, my.mean + my.sd * 2 ), c(0,0)) lines(c(my.mean,my.mean), c(0,my.dnorm(my.mean)), lty=2, col ="blue", lwd = 3) #########
Link: R_old_tips2(1916d)
Rの備忘録(3952d)
R_正規分布のプロット図(6185d)
Last-modified: 2010-06-13 (日) 16:14:51 (5236d)