Exercise 5.1 - Nuclear Decays

In this exercise we shall simulate the measurement of the number of radioactive decays measured in one second from a particular radioactive source. You will choose the number of times to repeat the measurement, and the estimated mean and the estimated standard deviation will be calculated and a histogram of the data will be displayed.

Choose the number of times to repeat the measurement:

When through with this exercise you should answer the following questions:

  1. Does the width of the "curve" as measured by the estimated standard deviation depend on the number of times the measurement is repeated?
  2. The simulated events were generated by a Monte Carlo technique, named after the casino. This algorithm does an excellent job of simulating what real data would look like. The true mean and standard deviation used in the Monte Carlo calculation are integers. What are their values?
  3. For a given number of repeated measurements, the values of the estimated standard deviation were unlikely to ever come out exactly equal to your answer to Question 2, but instead for a number of trials exhibit a spread of values. Qualitatively, how does the width of this spread of values depend on the number of repeated measurements?
  4. Can you find any relationship between the two numbers that were your answer to Question 2 above? A correct answer to this question matches the relationship between the mean and standard deviation for real radioactive decays.
  5. As of January 18, 2001 hockey player Mats Sundin of the Toronto Maple Leafs had scored 16 goals in the season. Some were "lucky" goals and at other times he had excellent scoring chances that failed to find the net. From your answer to Question 4, what is a reasonable guess of the statistical uncertainty in the number of goals he has scored.

This document and the Perl code to generate the simulation were written by David M. Harrison, January 2001.
This is $Revision: 1.6 $, $Date: 2001/05/31 14:45:11 $ (year/month/day) UTC.