An infuriatingly simple question

Longkappa · August 2nd, 2004, 6:07 pm

Z = aX*bYwith VAR(X) and VAR(Y) known, what is VAR(Z)? don't assume that they're IID... I am having a hell of a hard time finding any reference to this on the web or in any books at hand.Could anyone help? thanks

MarcusCuda · August 2nd, 2004, 8:21 pm

Everyone seems to cite "Goodman, L.A. 1960. On the Exact Variance of Products. Journal of the American Statistical Association 55:708-713."I'll see if I a can dig up a copy of the Goodman article tomorrow.Also, http://www.arec.umd.edu/Publications/pa ... /02-09.pdf has a brief description in the endnotes. This also has the formula:http://www.ce.umn.edu/classes/spring04/ ... hmetic.pdf

MarcusCuda · August 3rd, 2004, 12:47 pm

I could only locate the Goodman paper on JSTOR. If you have access to JSTOR, here is the link to the article:http://links.jstor.org/sici?sici=0162-1 ... .CO%3B2-3A discussion on approixmating the variance of a product can be found in "Sampling Methods For Censuses And Surveys"by Frank Yates. The first edition of the book is online at :http://www.archive.org/texts/texts-deta ... SurveysSee page 198