The application of the mean values derived from a large number of measurements to the annual physical examinations of cadets of the Naval Academy / by Henry G. Beyer.

  • Beyer, Henry Gustav, 1850-1918.
Date:
[between 1890 and 1899]
Catalogue details

Licence: Public Domain Mark

Credit: The application of the mean values derived from a large number of measurements to the annual physical examinations of cadets of the Naval Academy / by Henry G. Beyer. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    deviate to the same degree (+ d) from the mean height throughout his growth. In that case the law of growth for the type at a deviation of d from the mean is his law of growth. Otherwise he is an exception. This knowledge is furnished by the individualizing method while the generaliz- ing method is of no assistance in this matter. (Porter.) It was according to the individualizing method that we were able to collect the data with regard to the measurements of 3,415 naval cadets, which measurements form the basis of the calculations embodied in the present paper. By far the great majority of the cadets have been measured annually for four successive years and once again after their two years’ cruise, or before their final examination; some of course dropped out before completing their four years’ course and hence could not have been measured as many times as those remaining. In accordance with the above method, the data were arranged according to age, the means for each age determined, as well as the deviations from the mean. The probable deviation from the median value of a series containing many measure- 28 ments may be calculated by the approximation formula: —■ d — 0.8453 Where d = probable deviation, 8 = deviation of individual from median value, 28 = product of individual deviations, and n the total number of observations. For purposes of illustration see Table I. Table I.—Calculation of probable deviation (d) from average height {67.28 inches) of 598 naval cadets aged 18. Heights at 1 inch interval. 2 a 16 Heights at 1 inch interval. 2 4 26 75 76. 1 8. 72 8.72 65-66 65 1.28 83.20 74-75 2 7. 72 15. 44 64-65 28 2. 28 63. 84 73 74 4 6. 72 26. 88 63-64 12 3.28 39. 36 72 73 15 5.72 85. 80 62 63 7 4. 28 29. 96 71 72 27 4. 72 107. 44 61-62 3 5. 28 15.84 70 71 56 3. 72 208. 32 60 61 69 70 82 2. 72 223. 04 59-60 i 7. 28 7.28 68 69 95 1.72 .72 163 40 67-68 96 69* 12 598 1,176. 76 66 67 104 .28 29.12 Probable deviation, d = ± 0. = 1. 69 inches. Table No. II shows the values of the probable deviation yd) for each of the dimen- sions indicated and calculated for the different years given in one of the columns. In examining the values under “weight,” the uniformity is very striking. As to “height standing,” the probable deviation will be seen to slightly decrease from year to year until the age of 20 years lias been reached. The exception occurs at the fif- teenth year, at which the probable deviation is greatest, in accordance with the fact that that year marks the period in a boy’s life in which his growth is most rapid, hence also the greater deviation. In a general way the same gradual decrease, with the same exception, up to age 20 may be found in the column of the values under “perineal height.” There is likewise a gradual decrease in the probable deviation of the lung capacity up to 20 years of age, except that at age 14. This seems rather small, but the number of observations at that age is so small as not to be as reliable as the rest of the ages. Cadets are not allowed to enter at that age any longer, although they were formerly. Table II.— Values for probable deviation “ d.” Observations. Age. Weight. Hei gkt. Circum- ference of thorax. Lung capacity. Waist. Standing. Perineal. Tears. Founds. Inches. Inches. Inches. Cu.in. Inches. 23 14 10.31 1.87 1.34 1.20 9. 72 1.41 99 15 11.74 2. 53 1.51 1.47 25. 35 1.37 285 16 10.56 1.85 1.29 1. 47 24.51 1.32 497 17 10.14 1.76 1.25 1.46 23.03 1.23 490 18 10.98 1.69 1.22 1. 39 22. 48 1.51 550 19 10.14 1.57 .86 .93 20. 62 1.42 480 20 10.34 1.50 .98 1.30 22. 77 1.48 390 21 10.14 1. 52 1.69 1.20 21.75 1. 46 260 22 10. 29 1. 60 1.14 1.26 21.13 1.35 186 23 9. 51 1.45 1.12 1.15 20. 35 1.39 155 24 12. 67 1. 79 1.25 1.47 21.13 1.53
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