jtoL. 7, 1921 GENETICS: J. A. HARRIS ET AL. 219 



TABLE 3 



ERRORS OF PREDICTION OP THE RECORD OF A PERIOD OF MONTHS FROM THE 

 RECORD OF INDIVIDUAL PRECEDING MONTHS 



| PERIOD FOR MONTH USED AVERAGE DEVIATION AVERAGE DEVIATION SQ. ROOT OP MEAN 



WHICH AS BASE WITH REGARD TO SIGN WITHOUT REGARD TO SIGN SQ. DEVIATION 



PREDICTION op Actual Percentage Actual Percentage Actual Percentage 



is MADE PREDICTION deviation deviation deviation deviation deviation deviation 



Dec.-Oct. November +2.39 1.57 29.59 19.49 38.65 25.46 



Jan.-Oct. December +0.24 0.16 28.43 19.53 36.63 25.16 



Feb.-Oct. January +2.37 1.71 26.48 19.06 34.61 24.91 



|. Mar.-Oct. February +0.09 0.77 24.07 18.66 30.86 23.92 



Apr. -Oct. March -0.24 0.21 22.81 20.36 28.40 25.34 



i|May-Oct. April -4.00 4.23 21.36 22.59 .26.50 28.02 



Jjune-Oct. May +3.62 4.98 19.89 27.35 24.81. 34.11 



iju!y-Oct. June -2.86 5.34 17.62 32.91 21.44 40.04 



!JAug.-Oct. July -3.71 10.43 13.91 39.09 17.14 48.17 



Sept.-Oct. August -2.56 13.57 9.76 51.75 12.12 64.26 



October September -0.45 7.67 4.57 77.85 5.71 97.27 



\ The results of this investigation, taken as a whole, show that in the case 

 f a flock of White Leghorn fowl which is essentially identical in genetic 

 omposition and maintained under essentially uniform conditions from 

 ear to year it is quite possible to estimate annual egg production from the 

 :cord of either a single month or of two or three consecutive months with 



high degree of accuracy. The same is presumably true of other breeds 

 s well. This point is now under investigation. 



It is not possible to use the equations given in this paper for flocks differ- 

 ig greatly in genetic composition or in conditions of maintenance from 

 lat upon which these equations were based. The problem of the deter- 

 lination of corrective terms to be used when the equations are applied to 

 ocks other than that upon which they are based is now under investiga- 

 on. 



A detailed account of these investigations is now in press in Genetics. 



Alder and Egbert, Bull. Utah Agr. Exp. Sta., No. 162, 1918. 



&quot;Harris, Blakeslee and Warner, These PROCEEDINGS 3, 1917 (337-341) ; Harris, 

 lakeslee, Warner and Kirkpatrick, Genetics, 2, 1917 (36-77). 



3 Harris, Blakeslee and Kirkpatrick, These PROCEEDINGS 3, 1917 (565-569); 

 enetics, 3, 1918 (27-72). 



A range of five eggs was used in order to obtain a number of birds sufficiently large 

 -&amp;gt; reduce somewhat the irregularities due to the errors of random sampling. The 

 rors of prediction were in each case determined for classes of unit range. Grouping 



used for graphic representation merely. The average deviations represented by the 

 Tiit of the shaded zone are to be thought of as measured from a line perpendicular 

 &amp;gt; the ordinates and intersecting the prediction line on the mid-ordinate of the 5-egg 

 ass. 



