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F分布に関連する関数(df, pf, qf, rf)

三中信宏
Copyright (c) 2004 by MINAKA Nobuhiro. All rights reserved.


●F分布の密度関数(df)を表示
> x <- seq(0, 4, 0.01)
> plot(x, df(x, 15, 50), type="n")
> curve(df(x, 13, 50), type="l", add=T)


●F分布の確率分布関数(pf)を表示
> curve(pf(x, 13, 50), type="l", lty=3, add=T)


●5%点の表示
> abline(h=0.05)
> lower.alpha5 <- qf(0.05, 13, 50)
> lower.alpha5
[1] 0.4321874
> abline(v=lower.alpha5)
> points(lower.alpha5, 0.05, cex=3.0, pch="*")

> abline(h=0.95)
> upper.alpha5 <- qf(0.05, 13, 50, lower.tail = FALSE)
> upper.alpha5
[1] 1.921429
> abline(v=upper.alpha5)
> points(upper.alpha5, 0.95, cex=3.0, pch="*")


●1%点の表示
> abline(h=0.01, lty=2)
> lower.alpha1 <- qf(0.01, 13, 50)
> lower.alpha1
[1] 0.2962809
> abline(v=lower.alpha1, lty=2)
> points(lower.alpha1, 0.01, cex=3.0, pch="*")

> abline(h=0.99, lty=2)
> upper.alpha1 <- qf(0.01, 13, 50, lower.tail = FALSE)
> upper.alpha1
[1] 2.508328
> abline(v=upper.alpha1, lty=2)
> points(upper.alpha1, 0.99, cex=3.0, pch="*")


●F分布のパラメーター(1)――分子自由度n1を変える
> x <- seq(0, 4, 0.01)
> plot(x, df(x, 15, 50), type="n")
> title("F Distribution\nn1=13 -> 5")
> for (i in 1:5) curve(df(x, 13-2*(i-1), 50), type="l", add=T)


●F分布のパラメーター(2)――分母自由度n2を変える
> x <- seq(0, 4, 0.01)
> plot(x, df(x, 15, 50), type="n")
> title("F Distribution\nn2=50 -> 10")
> for (i in 1:5) curve(df(x, 13, 50-10*(i-1)), type="l", add=T)


●F分布のパラメーター(3)――分子と分母の自由度を同時に変える
> x <- seq(0, 4, 0.01)
> plot(x, df(x, 15, 50), type="n")
> title("F Distribution\nn1=13 -> 5\nn2=50 -> 10")
> for (i in 1:5) curve(df(x, 13-2*(i-1), 50-10*(i-1)), type="l", add=T)

Last Modified: 8 December 2004 by MINAKA Nobuhiro