How to plot multiple graphs using different values for one of the variables?

I am trying to plot frequency (f) vs alphat for different values of alphat. frequency is always a vector from 100 to 10,000 with increments of 100, given that the value of alphat changes for every differet value of sigmaR. My code is only plotting the first value of sigmaR (20). The goal is to have 6 different graphs one for each value of sigmaR but I am only getting one

clear all;
clc;

f=100:100:10000;
for sigmaR=20,60,8,450,35,5 ;
alphat=20.*log10(sigmaR.*f)-42.4

plot(f,alphat)

end

Answer 1

[VBBV]

for sigmaR=[20,60,8,450,35,5]   % put this in  [ ] 
    plot(f,alphat)
    hold on
end

Put the loop vector in [ ] and use hold on after plot

Answer 2

[Walter Roberson]

hold on

after the plot() call.

[Ahmed Ahmed]

It's still plotting only the first graph