Determing Resistance of metal with temperature coefficient of resistance

[eximius]

Homework Statement

I'm trying to determine R_0 and alpha (temperature coefficient of resistance) from results I obtained through an experiment. We have been given the first equation and been told that R_T is the resistance at temperature T in kelvin. R_273 is the resistance at temperature 273K and alpha is a constant called the temperature coefficient of resistance. I don't know what the material is therefore I have no idea of what alpha should be.

Homework Equations

1)R_T = R_273(1+alpha(T))
2)R_T = R_0(1+alpha(T))

The Attempt at a Solution

I created the attached graph to try and determine alpha through the gradient of the line, but no matter how i try and derive alpha and/or R_0, I simply can't get an answer that's gives valid results for R_T at other temperatures.

 

[edgepflow]

First, I think you want to write your equations in the form:

R_T = R_0(1+alpha(T - T0))

so when T = T0, then R_T = R_0

Then, I would re-arrange your equation into the standard form:

y = mx + b

And you can solve for alpha with linear regression or pick two good end-point. Metals get non-linear at cold temperatures (as your graph shows) so stay in the linear region.