I'm keep getting " index exceeds matrix dimension"

hey, I'm very new to matlab. We got an assignment to plot some data about ratings of cities in the USA, in 9 different catagories. (it is a famous data in MATLAB).

This is the assignment-

"Plot all the data for each city under one figure and add a legend containing category names. Use the xlabel, xlim, title, legend functions."

this is my code and the figure seems to come out right but i keep getting this warning- "In legend (line 118)

Index exceeds matrix dimensions."

r = figure(3);

hold on

for i= 1:size(names,1)

plot(ratings(:,i))

title('cities rankings by categories');

legend('climate','housing','health','crime','transportation','education','arts','recreation','economics');

xlabel('City ID');

xlim([0 329]);

end

I don't know what's the problem..cause I do get the figure.