If I understand you correctly you want a histogram that looks like this:
This can be achieved by using hold to overlay the resigned histogram over the total histogram.
To do so plot your first histogram:
bar( centers , n , 'b' )
Turn on hold to prevent overwriting the first histogram:
hold on
Plot your second histogram:
bar( centers , n2 , 'r' )
Finally, turn off hold when your are done:
hold off
The following code gives you an example for two randomly generated data sets dayMinsUnresigned and dayMinsResigned. To use this code with your data you will first have to sort dayMins into the two vectors. Logical indexing would be a good place to get started with that.
%Inputs
dayMinsUnresigned = 10*rand(1 , 100);
dayMinsResigned = 10*rand(1 , 100);
%Histogram for each input using the same centers
[nUnresigned , minuteCenters] = hist( dayMinsUnresigned );
nResigned = hist( dayMinsResigned, minuteCenters );
%Sum the bins so that the second data set appears above the first
nSum = nUnresigned + nResigned;
figure;
bar(minuteCenters , nSum , 'b' ) %create the total histogram
% turn on hold so you can add another histogram to the same axis
hold on
bar(minuteCenters , nResigned , 'r' )
% do not forget to turn off hold when you're done!
hold off
legend('Not Resigned' , 'Resigned' )
