K. Pkarson 



9 



whcre La iiiay l)c calculatril micu l'or all f'or /; = to 5 aiiil t'or valucs of Z = .S to 20 

 or tor all odd munbers of orclinates fnnii 7 to 41. 'I'hose values are giveii in thc 

 accoiiipaiiyiiig Taliio, wliicli will eiiable tliu ruadcr to readily find the correctivo 

 terui, bcariiig in inind tliat, if the nionient is even, />„ mu.st be muitiplied by 

 ym + yo> and that if it is odd it niust be muitiplied by i/m—>/o- 



Table of Currective Terms fov Moments of Trapezia. 



Ln = 



(n +!)(« + 2) 



(11) 0» the fitting of Pavabolic Gurves to given Data. 



Let US consider this probleni first froni thc standpoint of the niethod of least 

 sijuares. 



Let the parabola be of the (m — l)th order and ropresented by 



y = Co + Ci X + c, X- + . . . + c,i_, *-"-'. 



Let tis write for brevity 



Vr = S (x'l/), 



X/ = .S' (*■'■), 



where S denotes a sumniation extending to the values of x and >/ for every 

 Observation. Then proceeding to make 



S (y — Ca— Ci X — C.X- — ... — Cn-i *'" ')" 



Biometrika ii 



