R ggplot:加权CDF [英] R ggplot: Weighted CDF

问题描述

我想使用ggplot绘制加权CDF.一些非SO的旧讨论(例如，来自的此 2012年)表明这是不可能的，但我想加薪.

I'd like to plot a weighted CDF using ggplot. Some old non-SO discussions (e.g. this from 2012) suggest this is not possible, but thought I'd reraise.

例如，考虑以下数据:

df <- data.frame(x=sort(runif(100)), w=1:100)

我可以使用以下方式显示未加权的CDF

I can show an unweighted CDF with

ggplot(df, aes(x)) + stat_ecdf()

我如何用w加权呢?对于此示例，我希望使用x^2外观的函数，因为较大的数字具有较高的权重.

How would I weight this by w? For this example, I'd expect an x^2-looking function, since the larger numbers have higher weight.

推荐答案

您的答案有误.

这是计算加权ECDF的正确代码:

This is the right code to compute the weighted ECDF:

df <- df[order(df$x), ]  # Won't change anything since it was created sorted
df$cum.pct <- with(df, cumsum(w) / sum(w))
ggplot(df, aes(x, cum.pct)) + geom_line()

ECDF是一个函数F(a)，它等于观察值的权重(概率)之和，其中x<a除以权重之和.

The ECDF is a function F(a) equal to the sum of weights (probabilities) of observations where x<a divided by the total sum of weights.

但是这里有一个更令人满意的选项，它只是修改了ggplot2 stat_ecdf的原始代码: https://github.com/NicolasWoloszko/stat_ecdf_weighted

But here is a more satisfying option that simply modifies the original code of the ggplot2 stat_ecdf: https://github.com/NicolasWoloszko/stat_ecdf_weighted

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