Problem 3 
pdf[t_]:=2/(1+t)^3;   cdf[t_]:=t*(t+2)/(1+t)^2;
FilledPlot[{pdf[t],cdf[t]},{t,0,6}]

[Graphics:../Images/prob_gr_10.gif]

1-cdf[3]
[Graphics:../Images/prob_gr_11.gif]
(cdf[3]-cdf[2])/(1-cdf[2])
[Graphics:../Images/prob_gr_12.gif]

Converted by Mathematica      February 10, 2001