M = 2*rand(40,46)-1; % random residuals -1 to 1
ages = 50:95;
years = 1980:2019;
[A,Y] = meshgrid(ages,years);
idx = M > 0;
scatter(A(idx),Y(idx),[],[0 1 0],'filled') % green
hold on
scatter(A(~idx),Y(~idx),[],[1 0 0],'filled') % red
xlabel('Age')
ylabel('Year')
