xxxviii Tables for Statisticians and Biometrieians [XVIII — XX 



regard to the spaciugs of the correlation curves, the value of the equiprobable 

 correlation is under "03, say "027. In other words no significant association can be 

 asserted. 



In the case of „cr,. = 1941 we are thrown back on the original formulae*. In 

 the first place we must find P for the given value of ^\ i.e. "TOSO (see p. xxxv). 

 But for ;(' = 4 from formula (xxix). 



lV27ri, ^ \/27r ^j 



= 2 {-200,0578 + -280,0088 x -84142} 

 = •871,3256. 

 To obtain r we have to use the formula below, where „cr,. = '1941, and 



m = ^ ( ., — 3) , the /x„, /Xj, fx^ being the normal moment functions of Table IX. 



~ 24m^ ^'"" ^'' ^^ ~ ^'-' <^2^'')1 + 12L= ^^' ^^'^'^ ~ ^' ( V2^ir )j 



(xxxii). 



Substituting the values of ,|0-,. = -1941 and \'-liii = 4-852,107, we have for 



,- = •03, P = -90550, 



r = -04, P= -86501. 

 Whence for P = -87133, we have r = -038. 



We now turn to the three cases which fall inside Table XX. 



(2) Eye-colour, Father and Son. 



log x- = 2-1249 „o-,. = -0514, 



r = 0-5 log ;,(;= = 2-0942 



"°''' ~ '^ r = 6 log x= = 2-2748 



,-=:0-6 log x'= 2-1239 



,■ = 0-7 log X- = 2-2935. 



Linear differences will suffice 



,a, = -05 r = 0-5 + .^~ [1] = 0-517, 



.<r,. = -OG r = 0-G+;^[-l] = 0-601. 

 Hence ^a,- = -0514 gives 



r = -.517.+ ^^x-084 



= •517 +012 = -529. 



* Drapers' Company Reseiirch Memoirs. Biometric Series VII. " A Novel Method," etc. : see 

 pp. 1-2, 13. 



