\documentclass{standalone}
\standaloneconfig{border=2mm 2mm 2mm 2mm}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
\usetikzlibrary{calc}
\usetikzlibrary{shapes}


\begin{document}

\begin{tikzpicture}[scale=1.00]
    \draw (2,-0.1) -- (2,0.1) ;
    \node [below,text width=1cm,align=center, inner sep=0pt] at (2,-0.5)
    {\tiny{Experiment}};
    \node [below,text width=1cm,align=center, inner sep=0pt] at (2,-0.7)
    {\tiny{begins}};
    \draw (2,0) -- (2.5,0);
    \fill (2.5,0) circle (0.7pt) node [below] {\tiny A1};
    \draw[->] (2.5,0) -- ++(70:1.5cm) coordinate (A1)  node [midway, left]{\tiny {\(R_1\)}};
    \draw (2.5,0) -- (5,0);
    \fill (4.5,0) circle (0.7pt) node [below] {\tiny A2};
    \draw[->] (4.5,0) -- ++(70:1.5cm) coordinate (A2) node [midway, left] {\tiny {\(R_1\)}};
    \draw (4,0) -- (6.5,0);
    \fill (6.5,0) circle (0.7pt) node [below] {\tiny A3};
    \draw[->] (6.5,0) -- ++(70:1.5cm) coordinate (A3) node [midway, left] {\tiny {\(R_1\)}};
    \draw (6.5,0) -- (8.8,0);
    %zigzag
    \draw (8.8,0) -- (9.1,-0.7);
    \draw (9.1,-0.7) -- (9.1, 0.7);
    \draw (9.1,0.7) -- (9.3, 0);
    %
    \draw (9.3,0) -- (10, 0);
    \fill (10,0) circle (0.7pt) node [below] {\tiny A4};
    \draw[->] (10,0) -- ++(70:1.5cm) coordinate (A4) node [midway, left] {\tiny {\(R_1\)}};
    \node [below,text width=1cm,align=center, inner sep=0pt] at (10,-0.5)
    {\tiny{Experiment}};
    \node [below,text width=1cm,align=center, inner sep=0pt] at (10,-0.7)
    {\tiny{ends}};
    \node[rectangle, rounded corners=3pt, inner sep=2pt, outer sep=0pt, draw=black,  font=\scriptsize, line width=0.3pt]
    at ($(A1)+(0,0.3)$) {\tiny{WITHDRAWN}};
    \node[rectangle, rounded corners=3pt, inner sep=2pt, outer sep=0pt, draw=black,  font=\scriptsize, line width=0.3pt]
    at ($(A2)+(0,0.3)$) {\tiny{WITHDRAWN}};
    \node[rectangle, rounded corners=3pt, inner sep=2pt, outer sep=0pt, draw=black,  font=\scriptsize, line width=0.3pt]
    at ($(A3)+(0,0.3)$) {\tiny{WITHDRAWN}};
    \node[rectangle, rounded corners=3pt, inner sep=2pt, outer sep=0pt, draw=black,  font=\scriptsize, line width=0.3pt]
    at ($(A4)+(0,0.3)$) {\tiny{WITHDRAWN}};


\end{tikzpicture}
\end{document}