ClearAll; Clear[f,sf];
$DefaultFont = {"Times-Roman",10};
Needs["Graphics`Graphics`"];
njags = 100;
mean[c_]:= Gamma[1+1/c];
mu2 = mean[2];mu5 = mean[5];
m2 = 1/Sqrt[2];m5 = (4/5)^(1/5);
l2 = Graphics[{Dashing[{0.001,0.01}],Line[{{mu2,0},{mu2,f2[mu2]}}]}];
l5 = Graphics[{Dashing[{0.001,0.01}],Line[{{mu5,0},{mu5,f5[mu5]}}]}];
poly[a_,b_,f_]:= Join[Table[{a+i(b-a)/njags,f[a+i(b-a)/njags]},
				  {i,0,njags}],{{b,0},{a,0}}];
shade[a_,b_,c_,f_]:= Graphics[{GrayLevel[c],Polygon[poly[a,b,f]]}];
f[m_,z_]:= m z^(m-1) E^(-(z)^m);
f2[z_]:= f[2,z];f5[z_]:= f[5,z];
M2 = (Log[2])^(1/2);M5 = (Log[2])^(1/5);

ushading = Show[shade[0,M2,0.65,f2],Axes->True,
				PlotRange->{{0,2.75},{0,0.9}},
				Ticks->{{0.5,{M2,"M"},1.0,1.5,2.0,2.5},{0,0.25,0.5,0.75}},
				PlotLabel->"c = 2",
				AxesLabel->{"x/s","s f"}];
lshading = Show[shade[M5,2.75,0.65,f5],Axes->True,
				PlotRange->{{0,1.6},{0,2}},
				Ticks->{{0.5,{M5,"M"},1.5},{0,0.5,1,1.5,2}},
				PlotLabel->"c = 5",
				AxesLabel->{"x/s","s f"}];

plot[m_]:= Plot[f[m,z],{z,0.001,3},
		   PlotLabel->StringForm["m = ``",m]];
	
upper = Show[ushading,l2,plot[2]];
lower = Show[lshading,l5,plot[5]];
Show[GraphicsArray[{{upper},{lower}}],
		PlotLabel->"                   Figure 26.1\n
		Median of Weibull distribution\n
		           (Shaded area = 0.5)"]