The relations of general intelligence to certain mental and physical traits / Cyrus D. Mead.

  • Mead, Cyrus D. (Cyrus De Witt)
Date:
1916
Catalogue details

Licence: Public Domain Mark

Credit: The relations of general intelligence to certain mental and physical traits / Cyrus D. Mead. Source: Wellcome Collection.

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    TABLE II FREQUENCY TABLE. Norma Boys Walking Talking Months Frequency Months Frequency 11 2 9 2 12 3 10 2 13 5 11 1 14 8 12 1 15 4 13 1 16 2 14 1 15 3 16 2 17 2 18 5 19 1 20 2 21 1 30 1 25 1 11 means 10.5 to 11.5 months. 9 means 8.5 to 9.5 months. N=25 N=25 Median= 13.875 Median= 16.5 Guessed Average= 14 Guessed Average= 16 True Average= 14.28 True Average=15.76 A.D.= 1.64 A.D.=3.2 25 percentile= 12.75 25 percentile=12.75 75 percentile= 14.69 75 percentile= 18.25 Q.= .97* Q.= 2.75* * Approximate P.E. obtained by calculating the semi-inter quartile range. From Table II we see the age that normal boys begin to walk and talk; and from Table III the same for normal girls. Figures I and 2 show the distribution curves for the same. Judging from the general tendencies of 50 cases, we might say that: 1. Boys begin to walk at 13.875 months (using the median as a measure of central tendency), with a probable error of .97 month; and begin to talk at 16.5 months, with a probable error of 2.75 months. 2. Girls begin to walk at 13.21 months, with a probable error of 1.12 months; and begin to talk at 15.5 months, with a probable error of 2.68 months. 3. Girls walk and talk a ‘little earlier than boys. The same is true if we judge from the average accomplishment of 50 chil- dren. Using the A.D. as a measure of variability, boys are more variable than girls.
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