我正在尝试绘制几个卡方 cdf,并且我想绘制一条与之相交的垂直线,然后它达到某个值,例如 0.005。
假设我知道 y 值,如何找到相交的 x 值?
\documentclass{article}
\usepackage{pgfplots}
\pgfplotsset{width=10cm,compat=newest}
\begin{filecontents*}{data.csv}
0,0,0
0.05005,0.17702,0.00037825
0.1001,0.24829,0.00058426
0.15015,0.30161,0.00077812
0.2002,0.34544,0.00097319
0.25025,0.3831,0.0011743
0.3003,0.41631,0.001384
0.35035,0.44609,0.0016036
0.4004,0.47312,0.0018341
0.45045,0.49788,0.0020762
0.5005,0.52072,0.0023304
0.55055,0.54191,0.0025973
0.6006,0.56165,0.0028771
0.65065,0.58012,0.0031702
0.7007,0.59745,0.003477
0.75075,0.61376,0.0037977
0.8008,0.62915,0.0041325
0.85085,0.64369,0.0044819
0.9009,0.65746,0.0048459
0.95095,0.67052,0.0052249
1.001,0.68293,0.005619
\end{filecontents*}
\begin{document}
\begin{figure}
\centering
\begin{tikzpicture}
\begin{axis}[
xmin=0, xmax=50,
ymin=0, ymax=1,
grid=both,
minor tick num = 1,
major grid style = {lightgray},
minor grid style = {lightgray!25},
width=0.75\linewidth,
xlabel={$x$}, ylabel={$\text{cdf}(x)$},
legend pos=south east,]
\pgfplotstableread[col sep=comma]{data.csv}\data
\addplot[smooth, very thick, blue] table[x index = {0}, y index = {1}] {\data};
\addplot[smooth, very thick, red] table[x index = {0}, y index = {2}] {\data};
\legend{$\mathcal{H}_{0}$, $\mathcal{H}_{1}$};
\end{axis}
\end{tikzpicture}
\end{figure}
\end{document}