现代统计图形 - 科学网—博客
现代统计图形 - 科学网—博客
现代统计图形 - 科学网—博客
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5.1 直方图 61<br />
1 > # 注意:以下两行代码足够添加密度曲线,本代码只是为了美观效果<br />
2 > # hist(geyser$waiting, probability = TRUE, main = )<br />
3 > # lines(density(geyser[[waiting]]))<br />
4 > par(mar = c(1.8, 3, 0.5, 0.1), mgp = c(2, 0.5, 0))<br />
5 > data(geyser, package = "MASS")<br />
6 > hst = hist(geyser$waiting, probability = TRUE, main = "",<br />
7 + xlab = "waiting")<br />
8 > d = density(geyser$waiting)<br />
9 > polygon(c(min(d$x), d$x, max(d$x)), c(0, d$y, 0),<br />
10 + col = "lightgray", border = NA)<br />
11 > lines(d)<br />
12 > ht = NULL<br />
13 > brk = seq(40, 110, 5)<br />
14 > for (i in brk) ht = c(ht, d$y[which.min(abs(d$x -<br />
15 + i))])<br />
16 > segments(brk, 0, brk, ht, lty = 3)<br />
Density<br />
0.00 0.01 0.02 0.03 0.04<br />
40 50 60 70 80 90 100 110<br />
图 5.2: 直方图与密度曲线的结合:借助函数density()可以计算出数据的核<br />
密度估计,然后利用低层作图函数lines()将核密度估计曲线添加到直方图<br />
中。注意本图中其它低层作图函数的使用。