INTERRELA T/ONS///P OF ECO RECORDS 
101 
ing first year annual production to the productions of the indi¬ 
vidual months have already been provided for the White Leghorn 
breed as studied at Storrs (Harris, Blakeslee and Kirkpatrick, 
1918, p. 33-39, diag. 2-5) and for the Rhode Island Red breed as 
studied at Amherst (Harris and Goodale, 1922, diag. 
1-3). The form of the regression equation showing the relation¬ 
ship between second year total production and first year monthly 
production has also been investigated for this series of White 
Leghorn birds (Harris and Lewis, 1922, diag. 5-6). It 
seems unnecessary, therefore, to consider the equations showing 
the relationship between the annual record of the first year and 
the monthly records of this year in the present series. It does, 
however, seem worth while to determine whether a series of 
straight lines will represent reasonably well the relationship be¬ 
tween the records of the individual months of the second year 
and the annual record of the second year. 
The straight line regression equations for both the first and 
the second year are shown in table 4. 
The straight lines and the empirical means for the second year 
production are shown on the 12 figures of diagrams 2 and 3. 
While regression cannot be definitely asserted to be strictly 
linear in every instance (and will indeed probably be shown to 
be sensibly non-linear for certain months when sufficient biologi¬ 
cal data are available to make a crucial mathematical test possi¬ 
ble), it is clear that as a first approximation the straight lines 
represent the means reasonably well. 
The essential linearity of the regression of second year total 
production on the second year monthly productions shows that 
prediction equations of the type developed for first year produc¬ 
tion in the White Leghorn (Harris, Kirkpatrick, Blakeslee, 
Warner and Card, 1921) may, if it proves desirable, be developed 
for the prediction of total second year production from the records 
of the individual months. At present, adequate data for the 
calculation and testing of standard equations of this kind are not 
available. The increasing interest of those who have charge of 
the various contests in second year production will ultimately 
result in the collection of such data. 
2. The correlation betzveen the records of the individual months 
and the records of the remaining eleven months of the year. 
