STATISTICAL METHODS IN PROTOZOOLOGY 



461 



In any case in which it is desirahle to express the rate of change 

 of one variable with respect to another, and these variables plot on 

 arith-log paper in a linear fashion, this procedure may be used. 

 It should be noted that if y is declining as .v increases, the constant 

 B will be less than i. A value of B such as 0.96 would indicate 



dPM- 12 PM. 4 AM 8 AM 12 AM. 4 PM. 



TIME OF DAY 



Fig. z^' — Growth of Plasmodium pracox in the asexual stage. (Arith-log 



scale.) 



that a four per cent decrease in the y variable accompanies a 

 unit change of x. 



In many problems where an analytic expression of the rate 

 is not desired, the arith-log paper will still be found of great con- 

 venience in discussing representative rates of change. As an illus- 

 tration of the use of arith-log paper in such connection, see the 

 paper by Andrews and Sanders (1928). 



SUMMARY 



The present paper is the briefest possible outhne of certain ele- 

 mentary statistical procedures and may be found satisfactory as an 



