new;
feat=randn(10,3);
m=mean(feat);
v=var(feat);
st=std(feat);
cv=cov(feat);
cc=corrcoef(feat);

[xx,yy,zz]=ellipsoid(m(1),m(2),m(3),st(1),st(2),st(3),20);

figure;
set( gcf, 'name', 'Basic Statistics Demo');
plot3(feat(:,1),feat(:,2),feat(:,3),'o');
title( 'Samples, sample mean and STD ellipsoid');
axis equal; grid on; rotate3d on;
hold on
plot3(m(:,1),m(:,2),m(:,3),'xr','LineWidth',3,'MarkerSize',20);
surf( xx, yy, zz);
colormap gray;
alpha(0.25);
hold off;

break

fprintf( 'EXECURION PAUSED::Basic statistics demo::Type "return" to continue...\n');
keyboard;

% construct a multivariate (bivariate) normal distribution of size 100x3
% mean is 0 for both variables, covariance matrix is 3x3 
% and vectors are 100
feat = mvnrnd([0;0;0],[1 .9 .8;.9 1 .8;.8 .8 1],100);
m=mean(feat)
v=var(feat)
st=std(feat)
cv=cov(feat)
cc=corrcoef(feat)

[xx,yy,zz]=ellipsoid(m(1),m(2),m(3),cv(1,1),cv(1,2),cv(1,3),20);

figure;
set( gcf, 'name', 'Advanced Statistics Demo');
plot3(feat(:,1),feat(:,2),feat(:,3),'o');
title( 'Samples, sample mean and STD ellipsoid');
axis equal; grid on; rotate3d on;
hold on
plot3(m(:,1),m(:,2),m(:,3),'xr','LineWidth',3,'MarkerSize',20);
surf( xx, yy, zz);
colormap gray;
alpha(0.25);
hold off;