What data to use from the thermocouples

I received the following question, and wanted to make the answer available for public consumption:

"so the software generated two types of temps: Temperature(c) and CJC temp and two voltages:Voltage(V) and CJC Thermistor voltage. So I am wondering which voltage do I use to the K type formula and what temperature should I use to compare?"

A great question actually...so, to once again reference the scenario letter:

Please provide a comparison of the uncertainty in temperature and length measurements by the various methods. A simple heating experiment in a water bath will be sufficient for the thermometer evaluation.

So, the nice thing about that LabVIEW interface is that it already does all the calculations for you in the background using the CJC temperature and the measured voltage to determine the linearized temperature of the thermocouple. Of course, it is possible for you to go back and take the thermocouple voltage and CJC voltage and calculate a temperature (the formula is in the lab 1 handout and if you want a detailed description of the operation of a thermocouple you should come find me in office hours), however, do you really need to do this? Read what I posted from the scenario letter (I even provided a small hint), and what quantities you are comparing and you should be able to figure out what to use and what is necessary to do in this instance.