Finding the prediction interval for a linear regression is a little more complicated than just finding the St Dev of the various points. It may be convenient to define the uncertainty of p as the standard deviation of such fluctuations, but it is not the standard practice. You should perhaps check a stats book for more info on the topic.
A quick run of the data through Minitab suggests that the +/-1 stdev prediction interval (68.3% confidence level) for r = 0.62 is p = 30.25 +/- 6.5. This is half again as large as the interval you list. The size of the prediction interval also changes across the range of the graph.
A couple minor points.
1) The resistivity of Cu is about 10^-8, not 10^+8.
2) I get 4.004, not 4.04 for stdev, but that could be round off error in the calculations or the original data.
Tim Folkerts
-----Original Message-----
From: phys-l-bounces@carnot.physics.buffalo.edu on behalf of Ludwik Kowalski
Sent: Sun 8/5/2007 11:20 AM
To: Forum for Physics Educators
Subject: [Phys-l] calibration
I composed a short illustration on propagation of errors. Critical
comments will be appreciated.