horizon wrote:Thanks for the responce, subdork. OK, went out on the web and boned up on chi-squared test. Very informative, but leads me to another question.
Correct me if I am wrong - When using the chi-squared test to evaluate fair dice, we are saying that the observed variances can be attributed to "random fluctuations" when the chi-squared total is less than 11.07.
What if a signifcantly large number of the sample sets all have the same pattern of variance, for example the only significant portion of the chi-squared total comes from the same die face in each sample set. While these samples would be deemed fair according to the chi-squared test, surely they are not a statistically probable sample set and therefore can be classified as "un-random" using some other statistical analysis.
Thanks.
Some of the problems with this as mentioned above is that the chi-squared test doesn't measure how far off a single proportion is... for example it doesn't measure how far the number of sixes is from the norm, it measure the entire distribution at once. If the 6s were off in one test and the 2s were off in another, the chi-squared test could give you the same result, but it would not be further evidence that the distribution is flawed. It would be a better idea to pool the data and do the test over.
However! one could theoretically do the test several times, then average the values to test whether we're getting results that indicate the individuals in our collection have different luck. This could be to see if the program favors people with certain characteristics. Not a very likely problem here, but in certain instances where you might expect a bias it would be a valid analysis.
Note however, I don't think this method would prove anything about "streakyness" since I imagine that there are usually several people taking turns about the same time.
I taught an introductory level stats course, and one of the assignments was to flip a coin 100 times and record the results. Then I would make it a point to call out anybody that didn't have any long streaks as being liars who fudged their data
Anyway, I hate statistics as it's really an area where people can cheat and lie simply by not reporting all their findings... In the world of beauty like that of numbers, I don't like to see such base things .... I doubt anybody has continued to read this far... so I'll stop