Find Average using a While Loop

I am pretty new to MATLab and for my engineering class I have to find the average of a set of data values provided by my instructor. I had to create them as a text file and load them in, which I did successfully, but I don't know how to create a while loop in order to find the average. We also must use tic and toc to time the whole process. I would provide my code, but I haven't been able to start it because I have no clue where to even start. Thank you!