(* Modeling Market Share *)



sim = Table[

      (marketSize = 100;

        initialCokeShare = 0.5;

        cokeSwitcher = 0.1; pepsiSwitcher = .2;

        cokeShare = marketSize initialCokeShare;

        pepsiShare = marketSize - cokeShare;

        leaveCoke = 

          If[cokeShare == 0, 0, 

            Random[BinomialDistribution[cokeShare, cokeSwitcher]]];

        leavePepsi = 

          If[pepsiShare == 0, 0, 

            Random[BinomialDistribution[pepsiShare, pepsiSwitcher]]];

        vars = {{cokeShare, pepsiShare, leaveCoke, leavePepsi}};

        Do[

          vars = Append[

              vars, {c1 = 

                  Last[vars][[1]] - Last[vars][[3]] + Last[vars][[4]],

                c2 = marketSize - c1,

                If[c1 == 0, 0, Random[BinomialDistribution[c1, cokeSwitcher]]],

                If[c2 == 0, 0, Random[BinomialDistribution[c2, pepsiSwitcher]]]}], {51}];

        Map[Mean, Transpose[vars]] // N), {100}];



Map[Mean, Transpose[sim]]