Plot[PDF[ExponentialDistribution[1/18],x],{x,0,60}]

Plot[PDF[GammaDistribution[2,18],x],{x,0,60}]

CDF[GammaDistribution[2,18],30]//N

Problem 3

Table[
N[CDF[GammaDistribution[10,1],x]],
{x,1,20}]

As α gets larger, the Gamma distribution becomes more similar to the Normal distribution

g=Table[
N[CDF[GammaDistribution[100,1],x]],
{x,10,200,10}] (* x takes values from 10 to 200 in steps of 10 *)

n=Table[
N[CDF[NormalDistribution[100,10],x]],
{x,10,200,10}] (* x takes values from 10 to 200 in steps of 10 *)

g/n

ListPlot[{g,n},PlotLegends->{"gamma","normal"}]

Problem 4

Integrate[(x-a*b)^3  *1/(b^a*Gamma[a])*x^(a-1)*Exp[-x/b],{x,0,Infinity}]