286 Trans. Acad. Sci. of St. Louis. 
TABLE No. 7. 
THE THEORETICAL AND THE OBSERVED DISTRIBUTION OF THE HEIGHTS 
or 2192 Grrus, AGED 8. 
: Heights at Intervals of Theoretical 
: of + 0.5d. Distribution. Distribution. 
+ 5.04 136.86 Cm. 2 9 
1 i a 185.01 “ 6 8 
-+- 4.0 *§ 133.26 *¢ 12 18 
3.5 ** 131.31 27 27 
oh. 8.0 129.46 «< 54 57 
+ 2. ) se 127.61 Lad 104 
+ 2.0 * 125.76 148 150 
+ 2 es 123.91 sc 206 209 
a 3.0 0 122.06‘ 259 286 
+ 0.5 * 120.21 « 289 00 
0.0 * 118.36 «* 
— 0.5 6 116.51 * 2389 272 
ee? 114.66 259 O75 
ont ec 112.81 ‘ 206 196 
cen oe 110.96 * 148 196 
9.8.6 109.11 « 80 
—— 107.26 54 40 
— 3.5 * 105.41 « 27 26 
= *6 103.56 « 12 = 
— 4,5 101,71 6 3 
oe 99.86 « 9 : 
TOtMls coarse 9192 2192 
ee 
The curves in Plate I * give a graphic representation of the 
figures in Table No. 7. A glance at these curves shows that 
there is a close agreement between them, indicating that the 
individual observations out of which they are constructed are 
symmetrically grouped about a middle value typical of the 
whole, and proving that the material with which we have to 
deal satisfies the requirements of theory. 
The method of showing distribution just described is not 
the only method used for this purpose. Francis Galton f 
determines the actual distribution of the observations in a 
series at intervals of 5 or 10 per cent. from the median or 
50 ** percentile grade.”? The calculation of the median value 
_ (mean) or 50 percentile grade has already been described: 
_ that for the 5, 10, 20 and other percentile grades is similar in 
i 
'* The plates are placed after the index at the end of the number. 
Natural Inheritance. London, 1889 
