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AD010203

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Distribution authorized to U.S. Gov't, agencies only; Administrative/Operational Use; DEC 1952. Other requests shall be referred to Aero Medical Center, Wright Air Development Center, Wright -Patter son AFB, OH 45433.

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AMRL ltr, 25 Apr 1977

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THE "AVERAGE MAN"?

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NOTK.lv. ! )i >* tr iliti t •<> n of ilii>* report outside Government will be mndc only with the prior upprovnl of the Atfo Mcdic.il I .uborutorv, UAI)(.i.

1 RIGHT AIR UEVEIjOPMKNT CSNTF.R

technical note *-CRD yyl

THE '‘AVERAGE MAN'*?

Gilbert S. Daniels. 1*1 Lh W>iF (NSC) Aero Nerii’ iil laboratory

December 1952

HDO No. 69S-71

bright Air Development Cesier Air Research ■roil Development Communt! Veiled ,MJte» Air For-e

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FOREWORD

Tills Technical Note was prepared from statistics compiled by Antioch College, Yellow Springs, Ohio under AF Contract No. 18(600)-30. Research and Development Order No. 695-71, ,!USAF Personnel Body Anthropometry, " is the applicable project and 1st Lt Gilbert S. Daniels, U5AF (M3C), the project scientist.

Sincere acknowledgment is made to Mr. Edmund Churchill of Antioch College who compiled and prepared the appendix of this report.

INTHGDUCTION

The tendency to think- in torms of the "average man* ie a pitfall into which many pernons blunder when attempting to apply human body size data to design problems. Actually it ic virtually iispo&sible to find an "average nan" in the Air Force population, This is not becauuu of any unique traite of thia group ox men, but because of the great variability of bodily dimensions which ie characteristic of all men* It is the intent of this Technical Hote to point out and explain bods of the factors that lead to the difficulties arising from the use of "average* dimensions and to indicate to seme extent how they may be avoided*

The data on which this Technical Hote is based are the results of the Air Force Anthropometric Survey of 1950. There is, however, every reason to suppose that conclusions similar to th'se reported here would have been reached If the same type of analysis had been applied to body size data based on almost any group of people.

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THE " AVERAGE MAS"

The "Average Man" is a very prominent figure, at - general . ule he is used as an oversimplified means of describing the combined characteristics of a varied population. Thus we are presented with an "average man* who Is about 5 feet 9 inches tall although the population he represents may vary from under 5 feet to over 6 feet 6 inches in stature. Clearly, if we were to ise the 5 foot 8 inch dimension for the design of au opening such as a doorway, we would have a door through which the "average man", and indeed all of the people who are shorter than average, ccnld pae« ^ ' * ;ructod.

The taller poople, however, and these would represe*. . w aOuu 6 50/& o, > ~ ov*."1

population, would have to stoop to avoid hitting their neadr on top of the doorway. Obvious as this example say be, it does illustrate that design problems require the application of human dimensional data beyond the over- simplified and Inadequate dimensions of the "average man".

Data published (1) by or available through the Anthropology Section of the Aero Medical Laboratory make available the information needed by the project engineer or scientist for the design of Items where human dimensions are of importance. These data extend the description of a particular dimen- sion beyond the average and thereby make it possible to select a suitable range of the dimension as It occurs in the total population. Such o range say, of course, be limited to serve the particular project in question.

Thus If staturo is being considered, a range of from 5 feet 5 Inches to 6 feet 1 Inch Is shown to cover 90$ of the Air force population, the range having been trimmed to leave out the tallest $f> and shortest 5$ of the men.

If thM information Is used to design a doorway adequate for men 6 foot 1 inch In stature, 95$ of the total using group will be able to pass through the doorway without hitting their heads.

While the use of average dimensions is generally unsatisfactory even when only one dimension is being considered at a time, the Inadequacy of the "average man" method it compounded many times when more than one dimen- sion is to be considered in a design problem. As an abstract representation of • mythical Individual most ropresentatlve of a given population, the "average awn" is convenient to grasp in our minds. Unfortunately he doesn't exist. Instead of being the easiest individual of a group to provide for, and the most common, the "average man" is in reality a very rare specimen and very hard to fit,

The fallacy of the "average man" concept is further illuctratod by a stady based on body measurements made on over hfc^0 Air Fore*- flying personnel. From a total of 13? available measurements a smaller group, all useful in clothing design selected. (Measurements applicable to other problems such as cockpit layout or seat design could equally veil have boon chosen; thoy would luue given much t.io oano results). The records of tho u.oOO-pJ’.ts nor. *«■.-(■ then examined to see how many of these men, if (i i.y , could t-e consiacrod average in all of the selected measurement s.

The exact method of deriving thifl range Is discussed in detail in the Anr’srdix hut for our inmodiafce purpose it is sufficient to state that lncludee approximately the middle 3 0 % of the total population. This i considerably more generous portion of the group than is included by th average value. In a r attempt to find an "average man", the "approxima average" ranges of each measurement were used as hurdles in a atep-by- elimination. *h»n the full sample of 4063 men vae examined for statu only 1055 fell within the acceptable range of "approximately averages group of 1055 was then culled for all of the raen of "average" stature also had "average’’ chest circumference. Only 302 of the group still q Elimination was continued with additional "average8 dimensionc until a end of 10 stops there was not a single individual remaining who fell v the ’'average" range for all measurements. This process of elimination gressod ca follows:

1. of tha original 4063 men

1055 were of approximately average stature

2. of these 1055 men

302 were also of approximately average chest- clrcuafi

3. of theae 302 r.ien

143 were aleo of approximately average sleeve length

4. of these l4;j men

73 ware also of approximately averagt crotch height

5. of these 73 men

28 were also of approximately average torso circmaf/

6. of these 28 man

12 were also of approximately average &i£ fl>r<rWfftr

7. of these 12 men

6 were alao of approximately average f&sk fii££iys££I

8* of these 6 men

3 were also of appr oiimatoly average jfifclet sJjC&HBtfll

9, of these 3 men

2 were also of approximately average jh&jgh

10. of these 2 men

0 were also of approximately average in crotch l.eite.tf

As a further step, TOO measurements made on one of the twn men remalr after the ninth step were examined, Cf theco only 62 fell within tJ»* of the middle 4u$ cf the total population; 29 were smaller (below tbe percentile) end 9 wore decidedly high (above the ?0th percentile). 1 lOTgo group of measurements madi on the other of these two "most new average" men showed much tho came pattern.

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The exact method of deriving this range is discussed in detail in the Aupendix hut for our iamediote purpose it is sufficient to state that it includes approximately the Biddle 30% of the total population. This is a considerably more generous portion of the group than is included by the exact average value. In an attempt to find an "average Ban", the "approximately average" ranges of each measurement were used as hurdles in a step-by-step elimination. When the full sample of 4063 men vae examined for stature, only 1055 fell within the acceptable range of "approximately average! This group of 1055 was then culled for all of the "ien of "average" stature who also had "average" chest circumference. Only 302 of the group still qualified. Slim? nation was continued with additional "average* dimensions until at the end of 10 steps there was not a single individual remaining who fell within the "average" range for all measurements. This process of elimination pro- gressed as follows:

1. of the original 4063 men

1053 were of approximately average staturo

2. of theee 1055

302 were also of approximately average chest- circumference

3. of these JOZ men

143 wars also of approximately average sleeve length

4. of these 143 men

73 were also of approximately average crotch height

5. of theee 73 men

28 were also of approximately average torso circumference

6. of these 28 man

12 were also of approximately average frip oircuaforance

?. of these 12 men

6 were also of approximately average neck circumference

8, of theee 6 men

3 were also of approximately average walBt circumference

9, of those 3 »en

2 were also of appr orimately average thicl^ circumference

10. of these 2 mon

0 were also of approximately average iu crotch length

As a further step, 100 measurements made or one of the two men remaining after the ninth step were explained. Of theco only 62 fell within tl *- range of the middle 4<$ of the total population: 29 were Biealler(bolcw the 30th percentile) anu 9 vert, decidedly high (aoove the 70th percentile). A iarc« c?o\\p of 00* euro monte mode on the other of then® two "most nearly average" rnn ohevod vnch the same pattern.

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Thus it can be seen that the "average nan" is a misleading and illusory concept as a basis for design criteria, and i3 particularly so vhon more than one dimension is being considered.

This Technical Note is not meant to d. scourage the project scientist, however, but merely to point out that the "average man" is usually not the solution to the design problem. Data are available which give a far more accurate description of range of human variability in body dimensions. r report is in progress (2) which fully describes each of 131 separate measurements of the Air Force flying population. While net yet available in published form, the data of this report are available through the Anthropology Section, Aero Medical Laboratory, Wright Air Development tenter, Wright- Patterson Air Force Base, Ohio, for use by government agencies and authorized contractors. In addition, the Section can make available dimensional design criteria for cases where more than one dimension is being considered at a time. Those multidimensional descriptions cannot be published in advance since each cno is a separate problem in itself and the number of such combinations of measurements approaches the infinite. For the benefit of project engineers whose problems are in the mu tl dimensional category, custom- designed solutions are available through the Anthropology Section, WCRDB-2, (Telephone 2-3230) .

PUBLICATION REVIEW

This report has been review and is approved. FOR. THE COMMANDING GENERAL:

£031

Colonel, USA? (MC)

Chief, Aero Medical Laboratory

Directorate of Research

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API- SHI) LX

Method of Deriving "Approximate Average"

Any definition of the "approximate average" is necessarily arbitrary.

The statistical average of a measurement is so narrow in range that the- oretically it includes only those Individuals whose measurement is exactly the same as the mean value* In practice this is expanded to include those individuals who fall within the same class interval as the mean value* Tor instance, since st&turo is tabulated in 1 centimeter Intervale, all of those individuals who are within plus and minus one half centimeter of the mean value would be considered average* This range would Include less than 6,U$ of the total group and is far too restricting for actual application of data* For the present purpose we have defined "average" wore liberally to include nil individualo who fall within a range of plue or .sinus three-tenths of a standard deviation of the mean value* This definition eeeme reasonable on two counts:

1. It results in ths middle 25 or 3<9> of a group being classified as approximately average on any one measurement.

2, It provides for moet measurements a value range which is at least the equivalent of a full clothing else (over l£ Inches on chest circumference, over 1 inch for sleeve length, etc.)

Actually it was necessary to use Halts which vers slightly different and, in general, slightly wider than those just described becauoo of the form In which the dmta were available* The limits were set to the nearest whole value of measurement, i.e*, the nearost whole centimeter.

Table I gives, for each of the mensureaonto us ad in this study, the values of the mean and the standard deviation, the range of values taken to be approximately average, and the number of men who fell within this range* Full descriptions of tbsse measurements and of the sen Included in the sample population can bs found in WADC Technical Report 5?-321 "Anthropometry of Flying Personnel-1950" (2).

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TABU! I

Haaeuroacnt	■Hgftfl			*N for Hau ot-!Asaaa
Stature	175.5 ce	6.2 cm	173.95*177.95 ca	1055
Choet Circumference	98.6 ca	6.2 cm	96.95-100.95 ca	1023
Sleeve Length	85.5 ca	3.8 ca	33.95-86.95 ca	1253
Crotch Height	83.4 ca	4.4 ca	81.95-84.95 ca	1105
Vertical Trunk Ciro.	164.6 ca	7.3 ca	162.95-166.95 ca	1093
Hip Clrcuaference (Sit.)	106.0 ca	7.2 ca	103.95-108.95 ca	1113
Heck Clrcuaference	38.0 ca	1.9 ca	36.95- 38.95 ca	1713
Valet Clrcuaference	81.4 ca	7.7 ca	78.95- 83.95 ca	990
Thigh Clrcuaference	56.9 ca	4,4 ca	54.95- 57.95 c«	1114
Crotch Length	71.6 ca	5.1 ca	69.95- 72.95 c«	1008

• B*««4 oo the original croup of 4,063 aen.

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BIBLIOGRAPHY

AF Technical Report 5501 Hunan Body Size in Military,. Aircraft and Personal Equipment. AF, AM 3, Wright Field, Dayton, Ohio (Unclassified)

WADC Technical Report 52-321, Anthropometry of Flying Personnel. 1950, Wright Air Development Center, Wright-Patterson Air Force Base, Ohio. (Unclassified) (In preparation)