Iain Toft wrote in news:[EMAIL PROTECTED]: > I'm no stats expert but would like to solve the following problem. > > Given two sets of scores... > > S1 = [38.37388112, 38.37471969, 38.40682618, 38.37863674, ..., > 38.39506964] > S2 = [22.40683282, 22.23267916, 22.08881316, 24.96633041, ..., > 21.8635192] > > I'd like some statistical evidence to show the scores attained in S2 > are inferior to those in S1. I can show the mean,min,max,stdev but > would like something with a little more clout. > > Each score in S2 was obtained in the same trial as S1 (that is the > scorer in S2 was competing against and in the same game/trial as the > scorer of S1). In this example S2 is clearly inferior in score, > however for other examples the difference is less prominent (in terms > of mean). How can I determine if scorer S2 is inferior to S1, from > what I can fathom out I need some kind of t test? > > There are 50 trials. > > Obvious two questions... > 1) What is a t test? > 2) How do I interpret the results?
There are two tests generally called "t-tests", one for independent samples and one for paired data. It appears you have paired data. In a paired t- test, you analyze the differences among pairs. The test generates a probability statement about how likely the mean differences are zero. T- tests use the sample variance to estimate the population variance (and standard deviation), which distinguishes them from z-tests where the variance (and standard deviation) are assumed known -- David Winsemius . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
