Miss M. I 1 ,.- ;:!. Mi (>. I". Vuli-, au.l 1W. K. 



the deviation in the age at death from the mean age at death, UK -a-u ! 

 in 5-vear units, must he multiplied in order to obtain the probable 

 deviation of the family from the mean family. 



II. Table of Regression Formulae or Curves. 



y = Size of Family, = Duration of Life. 



Serifs I. American Mothers. 



(a) For all lives. Straight line : 



y = 0-821 1+0-083,47-' 

 (/) For lives of 50 years and under. Straight line : 



y = -l-9881+0-163,233z 

 (c) For lives of 50 years and over. Straight line : 



/ - 3-5531 +0-044,748* 

 ('/) For all lives. Cubical parabola. Origin of x at 55 years and 1 

 unit = 5 years : 



// - 6-0208 + 0-328,474./- 0-035,056* 2 + 0-003,000.^ 



Origin of .< 



at birth and 



unit of .f one 



year. 



Series II. English 



(a) For all lives. Straight line : 



y = 3-1781 +0-043,819z Origin of x 



(V) For lives of 50 years and under. Straight line : at birth and 



// = - 0-6222 + 0'140,584.r f unit of r one 



(c) For lives of 50 years and over. Straight line : year. 



// = 4-9341 +0-018.810./- 



(d) For all lives. Cubical parabola. Origin of -x at 57 -5 years and 



unit = 5 years : 





y = 



-079,120x-0-052,719.r2 + 0- 



Series III. 



Fathers. 



() For all lives. Straight line : 



y - - 0-6819 + 0-105,G44./ 

 (/') For lives of 50 years and under. Straight line : 



y = - 2-6766 + 0-168.: 

 (r) For lives of 50 years and over. Straight line : 



y = 3-3976 + 0-043,726* 

 (rf) For all lives. Cubical parabola. Origin of x at 55 years and 

 unit = 5 years : 



y = 5-8 187 +0-363, 122^-0-047,438^ + 0-003,0. 



Origin <>f i 

 at birth and 

 f unit of x one 

 year. 



