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W S Cleveland

Publications and source records attributed to W S Cleveland.

3 recordsLinked to original sources

The use of numerical and graphical statistical methods in the analysis of data on learning to see complex random-dot stereograms.

Several numerical and graphical statistical methods are illustrated in an analysis of data from an experiment that investigated a hypothesis of Julesz that giving a person a priori information about the structure of a complex random-dot stereogram reduces the time needed to perceive it when it is viewed. The data are divided into two groups, one consisting of those observers who received no cue or verbal cues (NV) and the other consisting of those who received verbal-visual cues (VV). A quantile-quantile plot shows that the NV times (mean = 7.6) are longer than the VV times (mean =5.6). By using probability plots, it is shown that the perception times have an exponential probability distribution. A hypothesis test based upon this distribution is used to show that the difference between the NV and VV times has significance slightly below 0.05.

Cues↗

Photochemical air pollution: transport from the New York City area into Connecticut and Massachusetts.

Photochemical air pollution resulting from primary emissions in the New York City metropolitan area is transported by prevailing winds on a 300-kilometer northeast trajectory through Connecticut and as far as northeastern Massachusetts. As a result, southwestern Connecticut has the highest ozone concentrations in the region and there is a substantial increase in ozone concentrations in Massachusetts. The ozone concentrations of air entering the New York City metropolitan area are often already above the federal standard of 0.08 part per million, but the concentration distribution is well below concentration distributions at downwind sites in Connecticut.

Air Pollution↗