Chapter 2: posterior over urns

To perform this simulation we will simply add a layer of complexity to existing simulations, inserting a coin-toss at the start of each simulation run. The outcome of the coin-toss will then determine from which of the two simulated urns we draw:

REPS=100000;

Nballs1=98; Nballs2=148;

S=nan(REPS,1); %initialize success vector with NaN values

for n=1:REPS,

if rand<.5, S(n)=randi(Nballs1)>54;

else S(n)=randi(Nballs2)>74; end, end

mean(S)

Alternately, we could use the randi discrete pseudorandom number generator to produce simulated observations:

S=[randi(Nballs1,[REPS/2 1])>54; randi(Nballs2,[REPS/2 1])>74];

mean(S)