I was trying to prove the methods of moments in statistics using Matlab, where the first central moment should be equal to the mean and the second central moment should be equal to the variance.
Here I assume the mean of the distribution to be 105 and the variance being 10.
The following is my code:
clearvars
mu=105;
sigma2=10;
sigma = sqrt(sigma2);
xmin=mu-10*sigma2;
xmax=mu+10*sigma2;
n_grids = 100000;
x=linspace(xmin,xmax,n_grids);
fx = pdf('norm',x,mu,sigma);
fx = fx./sum(fx);
mu_verify = sum(x.*fx);
sigma2_verify = sum(((x-mu).^2).*fx);
sigma_2 = sum((x.^2).*fx) - mu_verify^2;
sigma2_verify and sigma_2 both should be 10, which is what I got from my PC, using Matlab R2022b 64 bit pc version.
However, when I switch to my Macbook Air (M2), using Matlab R2022b 64 bit mac version,
sigma2_verify and sigma_2 both became 3.1623, which is the same as sigma.
What can I do fix my Matlab on Macbook?
