NG52 eyepiece reticles, Chalkley point array

Chalkley Point Array - NG52This is used to quickly determine the relationship of components to each other using random sampling. Curtis gives an example of its application, where a researcher may want to see whether or not a certain drug affects the volume proportion of cell types in a given organ. With this graticule the proportion of points lying over the image of one type of component is statistically proportional to the area occupied by that component. The 25 points of the array are placed over the field of view at random, so that a comparison can be made between the number of points touching one type of component with the number touching the other type of component in each viewing. A series of observations will yield an increasingly accurate ratio of the comparative incidence of each type of particle.ReferenceA.S.C. Curtis. Medical and Biological Illustration, Vol. 10. pp 261-266. "Area and Volume Measurements by Random Sampling Methods." Read more