SECTION VII. COMPARISON OF VARIABILITIES. 



Standard Deviation of Stature. 



[a) The Whole Series. 



Let us consider the ioo different values of Standard Deviation 

 of Stature, which I have collected for purposes of comparison. 

 We notice the great range of variation of the S.D. Our extreme 

 values are 20/5 mm. and 97*0 mm. 



Grouping by units of 5 mm. we get the following distribu- 

 tion : — 



Distribution of 100 S.D. of Stature. 



Group 



29 

 to 



34 



34 

 to 



39 



39 

 to 



44 



44 

 to 



49 



49 

 to 



54 



54 

 to 



59 

 22 



59 

 to 



64 



64 

 to 



69 



69 

 to 



74 



74 

 to 



79 



79 

 to 



84 



84 

 to 

 89 



Frequency 



2 







4 



6 



13-5 



23'5 



10 



15 



3 







1 



We get 



Mean Value of Standard Deviation = 59'45 mm. 

 S.D. of Standard Deviation = 9*52 37 mm. 



P.E. of Mean Standard Deviation = V42 12 



We can now compare our Anglo-Indian S.D. with this Mean 

 Value : — 



Anglo-Indian S.D. =67*38 mm. 



Mean value of S.D. = 59*45 mm. 



Difference 



7'93 ± 6*42 mm. 



The difference 7*93 ± 6*42 mm. is not at all significant. 

 can find the probability of this difference, 



We 



x- D ia- y =0-83 approximately 

 9'524 



From Tables II, p, 



2 i(i+«) = 79 67 30 6 

 |(i -a) = -20 32 69 4. 



If we assume that our sample of 100 standard deviations is a 

 random or representative samples then 20*3% of all " homogene- 

 ous " races will have a S.D. greater than the Anglo-Indians, and 

 40*6% will differ more from the average value than Anglo-Indians. 



For Stature , the absolute variability (Standard Deviation) of 

 Anglo-Indians is thus not significantly greater than the average absolute 

 variability of homogeneous races. 



