Chapter 2: negative predictive value

This is simulated by sampling from all cases with negative results at the rate at which misses occur:

REPS=100000000;

HIT=[45 45 46 47]; %Hit data at each testing time

MISS=[5 5 4 3];

CR=[9027 9159 9237 9270];

FA=[923 791 713 680];

URNall=HIT+MISS+CR+FA; %size of urn containing all tests

URNhm=HIT+MISS; %urn containing all testees with disease

URNcf=CR+FA; %urn containing all testees without disease

for n=1:4,

Nlist=randi(URNall(n),[REPS 1])>(HIT(n)+FA(n)); %negative tests

Mlist=randi(CR(n)+MISS(n),[REPS 1])>CR(n); %Misses | neg test

pM(n)=sum(and(Nlist,Mlist))./sum(Nlist); end

disp(num2str(pM))