How to plot in for loop?

I'm trying to plot in loop a vector that has body mass index values. Purpose is to plot different weight category like undereight in blue and overweight in red and so on but i can't get my loop working properly. Can somebody help?

here is my code

data =[75 67 43 56 78 49 66 71 120
    164 168 152 169 170 157 167 181 170];

weight=data(1,:)
heigth=data(2,:)
bmi=weight./((heigth/100).^2);

for i = 1:length(bmi)
    if i<18.5
        scatter(heigth,weight,i,'b*')
    elseif i>24.9
        scatter(heigth,weight,i,'r*')
    else
        scatter(heigth,weight,i,'g*')
    end
end
grid on
xlabel('height (m)')
ylabel('weight (kg)')

Answer 1

[darova]

You re comparing wrong variable

if i<18.5        % maybe bmi(i) < 18.5

Forgot hold on

hold on

You draw all data together instead of one point

scatter(heigth,weight,i,'r*')    % maybe plot(heigth(i),weight(i),'r*')

[torre]

Thank you. Now I understand the logic in this code.