The median household income on two of Arizona's smallest Indian communities that operate casinos rose sharply over the past 10 years to exceed $50,000, an indication of legalized gambling's impact on the standard of living of some Native Americans. The median household income of the Yavapai-Prescott Tribe jumped to $51,000 from about $23,000 in 10 years, and it increased to $50,000 from $18,000 on the Fort McDowell Yavapai Nation, according to a Republic analysis of just-released U.S. census data. That is about $10,000 higher than the 1999 median household income for Phoenix and higher than the overall median for Mesa, Glendale and Tempe. 'For those tribes, that's great news,' said David LaSarte, executive director of the Arizona Indian Gaming Association, sponsor of Proposition 202. The proposition is one of three on the November ballot related to casino-style gambling to reservations. …LaSarte pointed out that the two tribes, which have about 1,000 members combined, represent only a small fraction of the state's Native American population, which numbers 255,879, according to 2000 census figures. …According to the latest census data, the median household income of most of Arizona's Native American communities remains far below the state average despite the growth of legalized gambling over the past 10 years. For example, the Navajo Nation, the state's largest tribe and one of six not involved with gaming, had a median household income of only $21,000. …Stephen Cornell, a professor of sociology at the University of Arizona who has analyzed the socioeconomic impact of tribal gaming in Arizona, said not all Indian communities are faring as well as the Fort McDowell and Yavapai-Prescott tribes. …In those two cases, he said,'it simply means that the benefits of gaming have to be distributed among fewer people.'