2 Carl C. Enghcrg 



II 



Distribution of 8,68q cases of enteric fever received into the Met- 

 ropolitan Asylums Board Hospitals, iS/i-pj. Karl Pearson, 

 Mathematical Theory of Evolution. Phil. Trans. A., vol. 

 1 86, pp. 390-91. 



The distribution here given for the 13 cases above 60 is what 

 Professor Pearson "considers" the most probable distribution for 

 those years. It seems that the hospital authorities "lumped" 

 their old patients, a practice fatal to accurate statistics. 



For convenience, we shall take five years as the unit. We 

 then get for the first four moments about the vertical through 

 — 2.5 years :^ 



VI =4. 294, V2=22.34i, V3=i37.05i, vi=967.682. 



Transforming to moments about the centroid vertical by means 

 of the relations 



we get: 



fjii=^vi — 4V1V3 -|- 6V1V2 — 3n* -f" »'2 — vi" - 



M-'=4-07i> f^3=7-599^ /^=69.3i4. 



^In practical computations, a vertical near the mean is used, but as I had 

 worked out these moments for another purpose lonsj before this paper was 

 thought of, I preferred to use them here rather than to do the whole work 

 over again. 



88 



