Re: [Phys-l] Data Analysis Questions

["Thomas O'Neill" <oneillth@jmu.edu>]

Bernard wrote:
> Obtain a bunch (how many is part of the exercise) and >measure their  
> resistance [all same labeled value and precision, obviously].

> bc suspects the data may be bimodal for an obvious reason, 

Actually, we do this as an introduction to uncertainty analysis and Student's t test.  We have our students pick a sample of twenty nominal 100 ohm resistors from a larger set of 100.  Measure the resistance of each.  They mix-up the first sample then re-measure the resistance of each resistor.  Then they measure the resistance of a second random sample of 20 from the set of 100 after throwing the first sample back in.  Finally they measure the resistance of a sample of 20 different resistors with the same nominal value. We have reels of old (>30 years) resistors that on average are about 5% higher than the new ones.  


The lab functions to introduce the students to multimeters, measurement uncertainties and questions like, "Do leads have resistance? and do we care?".  The scenario is that we wish to know if we should replace the first resistor with the second older resistor.

I have a formal lab write-up if anyone wishes to contact me off list. 
THO

Thomas O'Neill
Physics Instructor
Shenandoah Valley Governor's School
on leave to James Madison University 
THO

Thomas O'Neill
Physics Teacher in Residence
James Madison University
Shenandoah Valley Governor's School