t=-5:0.1:5;
f=[1 7 30
   3 11 50];
for i=1:6
    subplot(3,2,i)
    plot(t,tpdf(t,f(i))); hold on;
    plot(t,normpdf(t), '--');
    title(sprintf('g=%d', f(i)));
    if i<4 set(gca, 'xtick', [-4 -2 2 4]);
    else
        set(gca, 'xtick', -4:2:4);
    end
end
