PEPCEfJT 



OF 

 ■;«MPLE 





POLPiPIZED LIGHT 

 MEAN =19 69 MMxSEC 

 SAMPLE SIZE = 128 



UNP0LARI2ED LIGHT 

 MEAN = 8 34 MM.- SEC 

 SAMPLE SIZE = 130 



AUEPhGE LINEhP UELULlTf FOR EACH PATH v MM-- SEC' 



Figure 17-4. Average Linear Velocity Histograms for E. Vernalis in 

 Polarized Light and in Unpolarized Light. 



NOTE: Dashed lines denote the estimated mean of each distribution. 



We have made special provision within the Bugsystem for the manipulation 

 and statistical analysis of angular data. For example, the command 



*STAT/AN/FI BUGS.DI BUGS.ST 



produces a single data vector whose elements are statistical parameters 

 appropriate for circular distributions. These include the length and direction of 

 the mean vector (and related measures) as discussed by Batschelet (1). 

 Moreover, because the Bugsystem is well suited for investigations of animal 

 orientation (and because this is a major interest of one of its codevelopers) we 

 have implemented an extensive polar graphics package within the Bugsystem. 

 Figure 17-5 illustrates the use of polar wedge histograms to represent angular 

 density functions. 



More Advanced Statistical Operations 



These fall into two major categories: operators directed toward the analysis 

 of time dependence of behavioral variables and operators used to explore 

 mutual relationships between variables (e.g.. Figure 17-6). In the first category, 



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