I'll be the first to admit, I am not a math wiz. That said, please forgive my ignorance. I need to write a script for work that will take a given temperature/pressure and output the other (pressure/temperature). How do I find the function of the data?
First you should plot the data to see what it looks like. The ideal gas law suggests that if you have a closed volume and fixed amount of gas, the pressure will be proportional to the temperature. Excel will run a linear regression to give a straight line fit through the data and give you the equation of the line, so you could try that first. Excel will also do a higher order polynomial fit if the errors in the straight line fit are too large.