clear
a = 1;
N = 20;
p = 1/N;
nDados = 1000;
nREP = 20;
figure
plot( (0:5), poisspdf( (0:5), a ), '*--k' )
hold on
for qR = 1 : nREP
  n = binornd( N, p, nDados, 1 );
  nc = hist( n, 0:5 );
  F = nc/nDados;
  plot( (0:5), F, '.r' )
end