30 tikz 可以随机产生一些点列并绘制散点图吗?

我查了一下, tkz-euclide 可以在一个矩形内, 一条直线上, 一条线段上, 一个圆上产生随机点, 请问有没有办法在一条曲线附近, 或者一个三角形内产生随机点?谢谢!

我在 tikz 中找到一个功能, 勉强写了一个, 凑合用, 麻烦帮我看看可以改进吗? 谢谢哈!

\begin{tikzpicture}[xscale=.5,yscale=.6]
\tkzDefPoints{0/-4/O,12.5/-4/X,0/5/Y}
\draw[-stealth,thick](O)--(X)node[below]{观测时间};
\draw[-stealth,thick](O)--(Y)node[right]{残差};
\foreach \x in {1,2,...,10}
{
    \draw (\x,-4)--+(90:.3)node[below=.2]{\footnotesize \x 00};
}
\node[below]at(0,-4){\footnotesize 0};
\foreach \y in {-4,-3,...,4}
{
    \draw (0,\y)--+(0:.3)node[left=.2]{\footnotesize $\y$};
}
\foreach \j in {1,2,3}
{
    \foreach \i in {1,2,...,500}
    {
    \coordinate (T) at ({5+5*rand},{\j*rand});
    \tkzDrawPoints(T)
    }
}
\end{tikzpicture}

@u13203

\let\temptotalnum\totalnum
\begin{tikzpicture}
\foreach \x[count=\c] in {-5,-4.5,-4,...,5}{
  \coordinate (p\c) at(\x,0.4*\x*\x);
  \fill [red](p\c) circle [radius=4pt];
  \xdef\totalnum{\c}
}
\pgfmathparse{int(\totalnum/2)}
\let\halfnum\pgfmathresult
\foreach \c in {1,...,\totalnum}{
  \pgfmathparse{int((\halfnum-abs(\c-\halfnum)+1)^(2))}
  \let\repeattimes\pgfmathresult
  \foreach \n in {1,...,\repeattimes}{
    \pgfmathrand
    \let\randomx\pgfmathresult
    \pgfmathrand
    \let\randomy\pgfmathresult
    \pgfmathrandom{1}{20}
    \let\scalefactor\pgfmathresult
    \coordinate (r p\c) at ($(p\c)+\scalefactor*(\randomx,\randomy)$);
    \fill (r p\c) circle [radius=2pt];
  }
}
\end{tikzpicture}
\let\totalnum\temptotalnum
\let\temptotalnum\relax

非常感谢