K. Pkarson 3 



Taking Mv Galton's polygoii lor Lliu data of liS!)2 niiiutccn ordiiiatcH were 

 obtaiiied f'or si)eeds at equal intervals of a sccond, 29 — 28, 28 — 27 ... 11 — 10 fVoin 

 the observations on 1324 trottei'S. On an arbitrary scale these nincteen ordinates 

 are given in Column (1). In Coliiinii (2) are their logarithms to three figure.s. 

 Cohinin (.')) gives tliu (irst niDuieiil ?/ti aboiit the middle of the ränge 21 = 19. 

 Column (4) the second nioiiunt m.. about the sanio poinl. Froiu ?/*„, iHi, in. and /, 

 Xo, Xi and X. wcre foutid and hent-e c,,, e, and e.j (see p. 14). 



Thus 



2/„= '-1^; = 1-441,316, X, = -^ = - •181,.5G4, 



X„= '"■^, = •308,74.54. 

 " mj- 



Whence e„ = r092,205, e, = - -.544,692, e., = - -276,0143. 



These give us for the required parabola : 



7=1-441,316 j 1-092,20.J- -544,692 m --276,614 (^^ 



This may be thrown into the furin : 



F= 1-441,316 1 1-360,583 - -276,614 f* "J '''^' 

 where x = — 9-3575. 



1—2 



