The following SPSS syntax show hows to generate a sample with any mean and sd and then rescale to a given mean and sd. I just tried 3 kind of random variable functions from a couple dozen or so that are available in SPSS
I can't think offhand how to adjust for skewness and kurtosis. Why do you want to do this? * generate a sample with arbitrary mean and sd to given mean and sd. new file. set seed= 20030402. input program. loop #i = 1 to 50. compute x1 = rnd(rv.uniform(2,4)). compute x2 = rnd(rv.normal(2,4)). compute x3 = rnd(rv.lnormal(2,4)). end case. end loop. end file. end input program. * get a z-score . descriptives vars= x1 x2 x3 / statistics = mean stddev kurtosis skewness /save. compute y1 = 50 + (zx1*10). compute y2 = 50 + (zx2*10). compute y3 = 50 + (zx3*10). descriptives vars = x1 x2 x3 y1 y2 y3 zx1 zx2 zx3 /stats = mean stddev kurtosis skewness. Hope this helps. Art [EMAIL PROTECTED] Social Research Consultants University Park, MD USA (301) 864-5570 [EMAIL PROTECTED] wrote: > Hi All > > Is it possible to generate a sample that has a specific mean, SD (also > skewness, kurtosis)? > To be more specific, I do not want to sample from a given distribution > (like the normal distribution) that has a specific mean and SD. If > sampled from a normal distribution with a given mean and SD, of course > the mean of the sample is not the exact same as the mean of the normal > distribution. > I try to get a sample that has a previously given mean and SD (and also > if possible skewness and kurtosis). > > Does anybody know the mathematical approach to this question? And, does > anybody know a software package that does this perhaps, or an algorithm > to use to program my own thing? Some vague things, like moments, are in > my head but that is perhaps not the correct path. Others asked, > expressed it this way: Sampling from a normal distribution with > restriction (restriction that the mean is exactly the given mean). > > Thanks Toby > > > > > mean = (sum xi) / N > > variance = (sum (xi - mu) ^ 2) / N > > skewness = (sum (xi - mu) ^ 3) / (N sdev ^ 3) > > kurtosis = (sum (xi - mu) ^ 4) / (N sdev ^ 4) . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
