fig=Show[
DiscretePlot[PDF[PoissonDistribution[20],k],{k,0,40},PlotRange->{{0,40},{0,0.1}},Prolog->{LightGray,Rectangle[{0,0},{40,0.1}]},
PlotMarkers->Automatic,
Frame->True,
FrameStyle->{{Thick},{Thick},{Thick},{Thick}},FrameTicks->{{{0,0},{10,10,{0.03,0}},{20,20,{0.03,0}},{30,30,{0.03,0}},{40,40}},{{0,0},{0.02,0.02,{0.03,0}},{0.04,0.04,{0.03,0}},{0.06,0.06,{0.03,0}},{0.08,0.08,{0.03,0}},{0.1,0.1}},{{0,"",{0.03,0}},{10,"",{0.03,0}},{20,"",{0.03,0}},{30,"",{0.03,0}},{40,"",{0.03,0}}},{{0,"",{0.03,0}},{0.02,"",{0.03,0}},{0.04,"",{0.03,0}},{0.06,"",{0.03,0}},{0.08,"",{0.03,0}}}},
FrameTicksStyle->24,
PlotLabel->Style["The Poisson distribution",24],FrameLabel->{Style["k",24],Style["prob(k|μ)",24]}],
Graphics[{
Text[Style["μ = 20",24],{32,0.08}]}],
ImageSize->72 7]
Export["/Users/ihn/Documents/Teaching/VP-Leitung/DataAnalysis/2013NewProgram/SoftwareVariants/Mathematica/poisson_Mathematica.pdf",fig]