An advertiser purchases online Ad impressions and wants to achieve a certain reach over a specified period of time. How many impressions does he have to purchase? The page-per-user distribution is known. I've published a solution on my web site, at datashaping.com/internet.shtml. However, I am wondering if more general results are available. Thanks. Vincent Granville, Ph.D. www.datashaping.com ================================================================= Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =================================================================