如何绘制尖头弧？

Question

如何用 tikz 为这些数据绘制累积曲线？

Answer 1

使用 pgfplots 会容易得多。

\documentclass[tikz,border=3.14pt]{standalone}
\usetikzlibrary{decorations.pathreplacing}
\begin{document}
\begin{tikzpicture}[scale=0.1]
\draw[thick,-latex] (0,0) -- (115,0) node[below] {marks};
\draw[thick,-latex] (0,0) -- (0,105) node[left] {students};
\xdef\Lst{(20,0)}
\xdef\oldY{0}
\foreach \Y [count=\X] in {14,6,10,20,30,8,12}
{\pgfmathtruncatemacro{\newX}{10*(\X+2)}
\pgfmathsetmacro{\newY}{\oldY+\Y}
\draw[thick,decoration=brace,decorate] (-1,\oldY) -- (-1,\newY)
            node[midway,left]
            {\Y~};
\draw[dotted] (0,\newY) -- (\newX,\newY);
\draw[dotted] (\newX,\newY) -- (\newX,0) node[below]{\newX};
\xdef\oldY{\newY}
\xdef\Lst{\Lst (\newX,\newY)}
}
\xdef\Lst{\Lst}
\draw[blue,thick,smooth] (0,0) -- plot[smooth,tension=0.3] coordinates \Lst 
-- (110,100);
\end{tikzpicture}
\end{document}

Answer 2

PSTricks 解决方案只是为了好玩。

\documentclass[pstricks]{standalone}
\usepackage{pst-plot,filecontents}

\begin{filecontents*}{test.data}
30      0
40      14
50      20
60      30
70      50
80      80 
90      88
100     100
\end{filecontents*}

\newpsstyle{mygrid}
{
    Dy=10,
    Dx=5,
    Ox=30,
    tickwidth=1.2pt,
    subticksize=1,
    xsubticks=5,
    ysubticks=5,
    subtickcolor=gray,
    subtickwidth=.8pt,
    xAxisLabel=\huge Marks,
    xAxisLabelPos={c,-5},
    yAxisLabel=\huge Cumulative Frequency,
    yAxisLabelPos={-5,c},
    llx=-2,
    lly=-2,
    urx=1,
    ury=1,  
}
\readdata{\mydata}{test.data}
\begin{document}
\begin{psgraph}[style=mygrid,xticksize=0 100,yticksize=0 70](30,0)(100,100){15cm}{20cm}
\listplot[plotstyle=cspline,linecolor=red,linewidth=2.4pt,showpoints]{\mydata}
\end{psgraph}
\end{document}