Hi On Tue, 7 Nov 2000, Nathalie Cote wrote: > Suppose you were in a Methods or Statistics class in which you had to design > a study, create the materials, collect some of the data, and then use the > data from this partial sample to simulate or fill in fictitious data for the > rest of the sample. > > Let's say, for example, that you've collected scores on self-esteem and body > image instruments from 10 college men and 10 college women, and you want to > use those data as the basis for generating fake data for 40 more women and > 40 more men. The data will then be analyzed for correlations between the > measures and differences between men and women on each measure and on the > correlations. I do two variations of this for my honours methods and stats class. (1) They work on individualized assignments that are computer generated. I use SPSS algorithms for generating samples from known populations (e.g., specified mu, sigma, rho, ...) and they include their students numbers as part of the SET SEED= value. SEED determines the actual data. So you could use the 10 observations to "estimate" mu, sigma, and rho, and then plug those values into the SPSS routines. When I get into more complex situations (e.g., multiple regression, factorial anovas) there is some "trial and error" work in getting realistic data. (2) We also do a class project each term, where we design a study, develop measures, etc. Ideally we then run a study with 100 or more real subjects. I give them algorithms to sample a specified number of observations out of the entire data set for their personal analyses and writeups. Occasionally there has not been enough time to collect full data so we end up with just data for the class (30-40 students). In those cases, I have "replicated" data set. That is, simply add the set of observations to itself a specified number of times, and then sample from this expanded set. Ten might be a little low to do this approach on, depending on what you want the final n to be. Best wishes Jim ============================================================================ James M. Clark (204) 786-9757 Department of Psychology (204) 774-4134 Fax University of Winnipeg 4L05D Winnipeg, Manitoba R3B 2E9 [EMAIL PROTECTED] CANADA http://www.uwinnipeg.ca/~clark ============================================================================
