How do I modify the code to get a plot?

The program only run the result with a blank plot, how should I change my code to get a plot? My code is like this below

for t=0:0.05:5
    T=170-22*t
if T>=120
    G=(3.98*10^7)*exp(-6270/(8.314*(T-30)))*exp(-2.55*10^5/((T+273)*(200-T)))
else
    G=(4.81*10^11)*exp(-6270/(8.314*(T-30)))*exp(-5.51*10^5/((T+273)*(200-T)))
end
plot(t,G);
axis([0,5,0,5]);
xlabel('Time');
ylabel('G')
end

Thank you a lot!!!

Answer 1

[Birdman]

t=0:0.05:5;
for i=1:numel(t)
    T(i)=170-22*t(i);
if T(i)>=120
    G(i)=(3.98*10^7)*exp(-6270/(8.314*(T(i)-30)))*exp(-2.55*10^5/((T(i)+273)*(200-T(i))));
else
    G(i)=(4.81*10^11)*exp(-6270/(8.314*(T(i)-30)))*exp(-5.51*10^5/((T(i)+273)*(200-T(i))));
end
end
plot(t,G);
axis([0,5,0,5]);
xlabel('Time');
ylabel('G')

[YuChe Kao]

Thank you a lot Birdman