How to use bar function

Hi members.For example I have a=[1 2], b=[3 4]. I want to compare two values, and I use bar function. But, I do not know how to combine two values in a plot, print like this figure (Element 9, and 10). Can you help me. Thank you

Answer 1

[madhan ravi]

An example:

y = [75 91 105 123.5 131 150 179 203 226 249 281.5];
bar(y,0.4,'b')
hold on
y1=[75.1 125]
bar([2.5 3.5],y1,0.4,'m')
legend({'1st bar','2nd bar'})

[Tran Hoa]

Thank you very much.

[madhan ravi]

Anytime :)