function CIRatio()

N=1000;  % Number of runs to perform
InsideCI=0;  % Initialize the count of thenumber of means inside the C.I.
for runNum=1:N
    x=randn(1,100);
    lowerBound=mean(x)-1.96.*std(x)./sqrt(length(x));
    upperBound=mean(x)+1.96.*std(x)./sqrt(length(x));
    if lowerBound<0 && upperBound >0
        InsideCI=InsideCI+1;
    end
end

% Because we're finding the 95% confidence interval, the ratio 
% of the number of means falling outside the confidence interval
% should be close to 0.05 (i.e. 5%):
RatioOutsideCI=((N-InsideCI)/N)