Here is the MatLAB code to plot data from Excel. First I exported my x, intensity data from Excel to a .csv file named single.csv. Then I did the following:

>> load single.csv
>> [n,p] = size(single)

n =

3456

p =

>> x = single(1:3455,1);
>> y = single(1:3455,2);
>> plot(x,y)

Now all you need to do is to model the single slit plotting so that the x axis is the same scale (cm would be most useful.) and plot the two graphs together on the same plot.

You can use the command:

>>hold on

to plot multiple graphs together. To clear the graph window, use

>>clf();

To make MatLAB stop plotting graphs together, use:

>>hold off