function Mpopx(p,N,M)
% Multiple simulations (M) of MCMC 
% for decaying populations
for i=1:M
    v = popx(p,N);
    sumLen(i) = length(v);
    Pop2(i) = v(2);
    Pop3(i) = v(3);
end
MeanLength = mean(sumLen)
STDLen = std(sumLen)
MeanPop2 = mean(Pop2)
STDPop2 = std(Pop2)
MeanPop3 = mean(Pop3)
STDPop3 = std(Pop3)