Earth's Surface Water Percentage?

A hands-on activity is used to illustrate standard point and interval estimates of a proportion. Since the proportion is more or less known, the accuracy of these estimates can be assessed. A hypothesis test associated with the interval estimate is also given.     

Lessons learned from unsuccessful experiences

This is the first guest column for “Managing Technology”. We hope it typifies the central theme of challenges to managers presented by information technology and the lessons we may share from their application. This essay is of signal interest, appearing as it does at a watershed in library automation. We may expect a wholesale shift in the next several years from single machine integrated systems to distributed computing technologies and a client/server model. The five “lessons learned” in the Oklahoma State experience will be broadly applicable in the next wave of library automation.—C.B.L.     

Children's Understanding of the Stream of Consciousness

Children and adults were tested for their understanding that there is a virtually continuous flow of mental content in a waking person, a "stream of consciousness" that continues to run even when the person is not examining stimuli perceptually or trying to solve a problem. There was a marked increase with age from preschool to adulthood in subjects' tendency to say that a person who was just waiting quietly was having "some thoughts and ideas" rather than "a mind empty of thoughts and ideas." 4-year-olds also tended to say that the mind of a waiting person was "not doing anything," whether that person was another individual or themselves, and that a person who wanted to could keep his or her "mind completely empty of all thoughts and ideas" for 3 min. These results suggest that preschoolers' conceptions of people's mental lives may be quite different from those of older children and adults.