Experimental statistics for undergraduates. I

Abstract

A description is given of an experiment to demonstrate the buildup of Poisson distributions with very high precision. Mean values up to 100 can be obtained, which enables a critical comparison of distributions with different means. By using small numbers of sampling periods, it is also possible to show how the means are themselves distributed, and to show that the standard deviation of the means is equal to σ/N1/2, where σ is the standard deviation of the ’’infinite’’ distribution and N is the number of sampling periods. Dead-time effects are also investigated experimentally.

Microprocessor projects in a physics laboratory

“…The present author has previously published work on student experiments to demonstrate Poisson distributions, and Chi-squared fits as they are used in physics (MacLeod et al 1976, andMacLeod 1980a). The context of this previous work is to count repeatedly, for fixed time intervals, the number of pulses in a nuclear particle detector, from the decay of a long lived radioactive source.…”

Introducing students to single photon detection with a reverse-biased LED in avalanche mode

“…Students are usually introduced to the statistics of random events using radioactive decay [9][10][11], even though the arrival of photons at a detector can obey the same statistical relationships. The results students get from a simple experiment using Cs-137 and a Geiger-Müller tube typically agree beautifully with theoretical predictions.…”