How to save out puts to graph later

Hello, I am working with data where I am taking the mean, the correlation coefficient, and variance to determine our confidence in the readings. I need to figure out how to: ~ tie the measurements to the time they where taken. ~ Save the outputs to the correct type of file to graph them (is .m any better than .txt? I have noticed .m is prone to crashing, but allows some manipulation of the data) ~be able to graph all outputs (as of now, when I try to use the plotting apps, I only get the first of 2000 times the mean was taken and would get a pretty sad graph) ~Graph them against time (Can I use the plot functions/apps on matlab or do I need to code it?). Thank you for any help