q1=0.1587;
q2=1-q1;
for n=0:1:4;
FAR=q1.^n.*(1+q2+q2.^2+q2.^3)/((q1.^n.*(1+q2+q2.^2+q2.^3)+(q2.^n.*(1+q1+q1.^2+q1.^3))))
plot(n,FAR, '*-');
hold on
end
xlim([-.5 4.5])
hold off
You are only plotting one point at a time, and MATLAB never draws connecting lines if you only plot one point at a time. If you want connecting lines you should record your n values and your results and plot() after the loop.
q1=0.1587;
q2=1-q1;
nvals = linspace(0,4);
num_n = length(nvals);
FAR = zeros(1, num_n);
for nidx = 1 : num_n
n = nvals(nidx);
FAR(nidx) = q1.^n.*(1+q2+q2.^2+q2.^3)/((q1.^n.*(1+q2+q2.^2+q2.^3)+(q2.^n.*(1+q1+q1.^2+q1.^3))));
end
plot(nvals, FAR)
xlim([-.5 4.5])
