280 Trans. Acad. Sci. of St. Louis. 
statement of the methods by which the mean and average are 
secured will suflice. 
By averAGEe (A) is meant the quotient obtained by divid- 
ing the sum (a) of the values (a) obtained in the individual 
measurements by the whole number of measurements (7). 
aa 
For ae (1) 
The calculation of the average height of girls, aged 9, will 
serve as an example. 
TABLE No. 4. 
THE CALCULATION OF THE AVERAGE HEIGHT OF ST. LovIS SCHOOL 
GIRLS, AGED 9. 
:| Number of ; . Number of 
el Observa- | Product. | Height 2 |” Observa- | Product. 
tie tions (a) Centi- tions (a); 
metres, (n) 7 metres. (n) y we 
168 1 168 134 25 3350 
167 133 31 4128 
166 132 29 3828 
165 131 62 8122 
64 130 78 10140 
163 129 91 11739 
162 128 119 15232 
161 127 132 16764 
160 1 160 126 148 18018 
159 125 162 20250 
7 124 141 17484 
123 wae 19926 
156 122 145 
155 121 130 15730 
54 120 145 17400 
153 119 97 11543 
152 118 94 11092 
151 117 69 8078 
150 116 59 6844 
149 115 47 5405 
114 30 3420 
47 113 18 2034 
46 112 11 1232 
45 111 10 1110 
sri 110 10 1100 
143 1 148 09 5 545 
142 2 284 108 1 108 
141 3 423 107 5 585 
140 2 280 106 3 318 
139 3 417 105 1 105 
138 9 1242 104 1 104 
137 12 1 1 103 
136 15 2040 102 
135 14 1890 101 
100 2 200 
Total...... n = 2122 ‘Sa—262358 
A un PEESOE 5 123.64 em. 
