- GeoRef, Copyright 2008, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society of America, Boulder, CO, United States
It is mathematically shown that for phi-normal size distributions when the frequency representation is changed from weight to number basis the mean of the distribution changes but the standard deviation (or variance) remains the same. An equation is derived which relates the means of the distributions and the constant variance. For approximate phi-normal distributions, however, the variance no longer remains constant, and the transformations from weight to number frequency or vice versa are not very accurate.