PMF and CDF

\documentclass[tikz,convert={outfile=\weibull_PMF.svg}]{standalone}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=1.7}

\begin{document}

\begin{tikzpicture}
[
    declare function={weibullpmf(\x,\a,\b) = \a^(\x^\b)-\a^((\x+1)^\b);}
]

\begin{axis}[
    axis lines=left,
    enlargelimits=upper,
    smooth,
    line width=1pt,
    samples at={-0.000000000000001,0.01,...,4},
    legend entries=
{
    $q=0.5 \quad\, \beta = 0.75$,
    $q=0.5 \quad\, \beta = 1   $,
    $q=0.5 \quad\, \beta = 2   $,
    $q=0.75\quad   \beta = 2  $
},
    legend cell align=left,
    ylabel={$\Pr\left(\mathbf{X}=x\right)$},
    xlabel={$x$}
]
\definecolor{color1}{RGB}{215,25,28  };
\definecolor{color2}{RGB}{253,174,97 };
\definecolor{color3}{RGB}{171,221,164};
\definecolor{color4}{RGB}{43,131,186 };

\addplot[draw=color1,dashed,forget plot]{weibullpmf(x, 0.5 , 0.75  )};
\addplot[draw=color1,
         fill=color1,
         only marks,
         samples at = {0,1,...,4},
         samples = 5,mark=*]            {weibullpmf(x, 0.5 , 0.75  )};

\addplot[draw=color2,dashed,forget plot]{weibullpmf(x, 0.5 , 1  )};
\addplot[draw=color2,
         fill=color2,
         only marks,
         samples at = {0,1,...,4},
         samples = 5,mark=*]            {weibullpmf(x, 0.5 , 1  )};

\addplot[draw=color3,dashed,forget plot]{weibullpmf(x, 0.5 , 2  )};
\addplot[draw=color3,
         fill=color3,
         only marks,
         samples at = {0,1,...,4},
         samples = 5,mark=*]            {weibullpmf(x, 0.5 , 2  )};

\addplot[draw=color4,dashed,forget plot]{weibullpmf(x, 0.75, 2  )};
\addplot[draw=color4,
         fill=color4,
         only marks,
         samples at = {0,1,...,4},
         samples = 5,mark=*]            {weibullpmf(x, 0.75, 2  )};
\end{axis}
\end{tikzpicture}

\begin{tikzpicture}
[
    declare function={weibullcmf(\x,\a,\b) = 1-\a^((\x+1)^\b);}
]

\begin{axis}[
    axis lines=left,
    enlargelimits=upper,
    smooth,
    line width=1pt,
    samples at={-0.000000000000001,0.01,...,4},
    legend entries=
{
    $q=0.5 \quad\, \beta = 0.75$,
    $q=0.5 \quad\, \beta = 1   $,
    $q=0.5 \quad\, \beta = 2   $,
    $q=0.75\quad   \beta = 2  $
},
    legend cell align=left,
    legend style={at={(0.98,0.02)},anchor=south east},
    ylabel={$\Pr\left(\mathbf{X}\leq x\right)$},
    xlabel={$x$}
]
\definecolor{color1}{RGB}{215,25,28  };
\definecolor{color2}{RGB}{253,174,97 };
\definecolor{color3}{RGB}{171,221,164};
\definecolor{color4}{RGB}{43,131,186 };

\addplot[draw=color1,dashed,forget plot]{weibullcmf(x, 0.5 , 0.75  )};
\addplot[draw=color1,
         fill=color1,
         only marks,
         samples at = {0,1,...,4},
         samples = 5,mark=*]            {weibullcmf(x, 0.5 , 0.75  )};

\addplot[draw=color2,dashed,forget plot]{weibullcmf(x, 0.5 , 1  )};
\addplot[draw=color2,
         fill=color2,
         only marks,
         samples at = {0,1,...,4},
         samples = 5,mark=*]            {weibullcmf(x, 0.5 , 1  )};

\addplot[draw=color3,dashed,forget plot]{weibullcmf(x, 0.5 , 2  )};
\addplot[draw=color3,
         fill=color3,
         only marks,
         samples at = {0,1,...,4},
         samples = 5,mark=*]            {weibullcmf(x, 0.5 , 2  )};

\addplot[draw=color4,dashed,forget plot]{weibullcmf(x, 0.75, 2  )};
\addplot[draw=color4,
         fill=color4,
         only marks,
         samples at = {0,1,...,4},
         samples = 5,mark=*]            {weibullcmf(x, 0.75, 2  )};
\end{axis}
\end{tikzpicture}
\end{document}

% ragulpr