According to http://global.mms.com/us/about/products/milkchocolate.jsp, 30% of M&M's are brown, 20% are yellow, 20% are red, and orange, blue, and green all account for 10% each. I've seen more than one elementary school teacher assign the problem of estimating these proportions from empirical data (such as thane@best.com presents), but not of course the problem of whether the differences are statistically significant. I would guess that the color proportions are primarily determined by aesthetics (single blue or green splotches on a brown background look more appealing to me than brown splotches on a blue or green background). Also, history plays a role: the original M&Ms were apparently all brown, with red, green and yellow all added in 1960. [Orange was introduced in 1976, blue in 1995. Red was yanked in 1976 and reinstated in 1987. Purple is scheduled to be added to the standard mix sometime soon.] -Thomas C