Orsdxy

I'm looking to create something like this in Tikz environment. Any tips? help?

The forest package allows you to recreate these figures.

documentclass{article}

usepackage[edges]{forest}

begin{document}

begin{forest}

for tree={rounded corners,text=white,font=sffamily,align=center,

grow'=east,forked edges,edge = {semithick, -stealth}, % see https://tex.stackexchange.com/a/333597/121799

anchor=west,l sep=2.5em,

if level=0{fill=green!60!black}{},

if level=1{fill=blue!70,minimum width={1.1*width("Merkmal beliebig")}}{},

if level=2{fill=blue,minimum width={1.1*width("Varianz unbekannt")}}{},

}

[Erwartungswert $mu$

 [Merkmal\ normalverteilt

  [Varianz bekannt]

  [Varianz unbekannt]

 ]

 [Merkmal beliebig\ verteilt]

]

end{forest}

bigskip



begin{forest}

for tree={rounded corners,text=white,font=sffamily,align=center,

grow'=east,forked edges,edge = {semithick, -stealth}, % see https://tex.stackexchange.com/a/333597/121799

anchor=west,l sep=3.5em,

if level=0{fill=green!60!black}{},

if level=1{fill=blue!70,minimum width={1.1*width("Merkmal beliebig")}}{},

}

[Varianz $sigma^2$

 [Merkmal\ normalverteilt

 ]

]

end{forest}

end{document}

An alternative to @marmot's nice answer:

documentclass[tikz,margin=3mm]{standalone}

usetikzlibrary{positioning}

begin{document}

begin{tikzpicture}[

    filv/.style={

        fill=green!50!black,

        font=color{white},

        rectangle,

        rounded corners=3pt,

        minimum width=3.5cm

    },

    selv/.style={

        fill=cyan!50!black,

        font=color{white},

        rectangle,

        rounded corners=3pt,

        minimum width=3.5cm,

        align=center

    },

    thlv/.style={

        fill=blue!30!black,

        font=color{white},

        rectangle,

        rounded corners=3pt,

        minimum width=3.5cm

    }

]

node[filv] (lv1-1) {Erwartungswert $mu$};

node[filv,below=2cm of lv1-1.south] (lv1-2) {Varianz $sigma^2$};

node[selv,above right=0.25cm and 1.5cm of lv1-1.east] (lv2-1) {Merkmal\ normalverteilt};

node[selv,below right=0.25cm and 1.5cm of lv1-1.east] (lv2-2) {Merkmal beliebig\ verteilt};

node[selv,right=1.5cm of lv1-2.east] (lv2-3) {Merkmal\ normalverteilt};

node[thlv,right=1.5cm of lv2-1.north east] (lv3-1) {Varianz bekannt};

node[thlv,right=1.5cm of lv2-1.south east] (lv3-2) {Varianz unbekannt};

draw[-latex] (lv1-2)--(lv2-3);

coordinate[right=0.75cm of lv1-1.east] (mid1);

coordinate[left=0.75cm of lv2-1.west] (mid1-a);

coordinate[left=0.75cm of lv2-2.west] (mid1-b);

draw (lv1-1)--(mid1);

draw[latex-latex] (lv2-2)--(mid1-b)--(mid1-a)--(lv2-1);

coordinate[right=0.75cm of lv2-1.east] (mid2);

coordinate[left=0.75cm of lv3-1.west] (mid2-a);

coordinate[left=0.75cm of lv3-2.west] (mid2-b);

draw (lv2-1)--(mid2);

draw[latex-latex] (lv3-2)--(mid2-b)--(mid2-a)--(lv3-1);

end{tikzpicture}

end{document}

for completness ... pure tikz version with using trees library:

documentclass{article}

usepackage{tikz}

 usetikzlibrary{arrows, positioning, trees}



begin{document}

begin{figure}

    tikzset{

  base/.style = {rounded corners,

                 text=white, font=sffamily,

                 minimum width=20ex,

                 align=center},

    L1/.style = {base, fill=teal},

    L2/.style = {base, fill=cyan!80!black},

    L3/.style = {base, fill=cyan!60!black},

   grow=east,

   edge from parent fork right,

   level distance = 37mm,

   level 1/.style = {sibling distance=16mm},

   level 2/.style = {sibling distance = 8mm},

    edge from parent/.style = {draw, semithick, -latex}

            }

    begin{tikzpicture}

node[L1] {Erwartungswert $mu$}

    child {node[L2] {Merkmal\ normalverteilt}

        child {node[L3] {Varianz bekannt}}

        child {node[L3] {Varianz unbekannt}}

          }

    child {node[L2] {Merkmal beliebig\ verteilt}}

    ;

    end{tikzpicture}



bigskip

    begin{tikzpicture}

node[L1] {Varianz $sigma^2$}

    child {node[L2] {Merkmal\ normalverteilt}}

   ;

    end{tikzpicture}

end{figure}

end{document}

of course, with forest is more simply and elegant solution