Margin of Error and Confidence Levels Made Simple
Margin of Error Calculator
Sample Size Calculator by Raosoft, Inc.
UNdata
Collected statistical databased from the UN--basically a free meta search across UN data. Covers population, education, employment, environment, and other statistics.
Census: More than 54 million disabled in U.S. - Health care- msnbc.com
US Census statistics on disabilities. If almost 20% of the population has some sort of disability, isn't that significant enough for us to take accessibility into consideration when developing online learning? If you want stats to justify why accessibility matters, this is a good place to start.
More than 54 million U.S. residents, or about 19 percent of the population, have some sort of disability, the U.S. Census Bureau reported.