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### Document

Number: 

# 20 ) ll-B- 9 Docket Number: 

# A-83-2 2

Printed 4/16/20089:12:06

AM Sheet 20of 97 P. 1P. 2

^ £DJ X

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# 53 2 UNITE D STATE S ENVIRONMENTA LPROTECTIO N AGENC Y Offic e o fAi rQualit yPlannin g an d Standard s Researc h Triangl e Park , Nort h Carolin a 2771 1 \ PRQlt 0 •3 0 JA N 1986

MEMORANDU

M SUBJECT : ACompariso n o fth e Precisio n Associate d wit h Alternativ e

Samplin g Plan s fo rOn e Versu s 3 Year s o fInformatio n an d Monthl yVersu s Quarterl yAveragin g Time s FROM : Willia m F
. Hunt , Jr
. C%^£*-~* ~ J* : Chief , Data Analysi s Sectio n (MD-14) TO : Joh n Haines , Chie f

Standard s Developmen t Sectio n B (MD-12 ) Thi s memorandu m supersede s m yearlie rmem

o o fDecembe r24 , 1985
. Th e compute rprogram , whic h calculate d th e precisio n estimate s i n th e earlie r memo, wa

s foun d t o contai n an error . The precisio n estimate s hav e bee n recalculate d fo rbot h monthl yan d quarterl yaveragin g times , fo ron e versu s 3 year s o finformatio n an d fo rfou rcategorie s o fmonitorin g sites : (1 ) al l sites , (2 ) source-oriente d site s wit h maximu m annua l quarterl y average s les s tha n th e curren t standar d o f1. 5 ug/m3 , (3 ) source-oriente d site s wit h maximu m annua l quarterl yaverage s greate rtha n th e curren t stand ard , an d (4 ) urban-maximu m concentratio n sites
. ASSUMPTION S Th e analysi s presente dinthi s memorandu m wil l serv e a s interi m guidance , whil e th e statistica l approac huse dt o calculatin g precisio ni s explore dmor e fully . A numbe r o f assumption s hav e bee nmad e i napplyin g th e formula s whic hfollow . Th e dat a ar e assume dt o b e approximatel y normall y distributed , autocorrelatio ni s assume dno t t o b e a factor , andthe confidenc e interva l i s determine dwithou t examinin g th e effec t tha t th e monthl y (quarterly ) averag e i s anorde r statistic . Wit hthes e simplifie dassumptions , th e statistica l approac huse d1nthi s memo provide s a nindicatio no f ho

w sampling frequency , 1 versu s 3 year s o f information , averagin g time s and site-type s relat e t o on e another . CALCULATINGPRECISION On e wa y o f focussin g o

nth e table s whic hfollow i s t o as kth e question : How many day s i na give ntime perio dshoul dthe ai r b e sampled , s o tha t the tru e monthl y

(quarterly ) arithmeti c mea nlie s withi n+1 0 percen t o f th e sampl e arithmeti c mean ?P. 3

The precisio n i s calculate d usin g th e followin g formula : 

# PI *-.*,

_

% 

# %^-^y^ </+ <$+ /,

_^ 1^ {7^% " ^ / - « * c

# O wher e tf = th e sampl e arithmeti cmonthl y(quarterly ) mean . £t-\ s th e t statisti cassociate d wit h n- 1 degree s o ffreedom
. s = th e sampl e monthl y(quarterly ) standar d deviation
. n = th e numbe ro fsample s take n fro m a finit e population
. N = th e tota l numbe ro fobservation s fo rth e finit e population , i.e
. N = 3 0 fo r1 month , N = 9 0 fo r1 quarter , etc
. V'' " 4i = finit e populatio n correctio n coefficien t (FPC)

. 1 - «.= th e leve l o fconfidence , i.e
. fo r* = 0.05 , the n 1 -* = 0.9 5 o ri t ma

yb e expecte d tha t 9 5 percen t o fth e confidenc e interval s wil l contai n th e tru e arithmeti cmean . Th e formul a whic h calculate s precisio n ca n b e reformulate d t o expres s precisio n as a percentag e o fth e mean . Thi s i s accomplishe d bydividin g th e Increment , +_t ;-*/,

. V>n ; JV-"" V %
. b yyan d multiplyin g b y100
. I n doin g so , a ne

wvariabl e i s created , s/^ , o rth e coefficien t o fvariation , (c)
. Precisio n ca n no wb e expresse d as :

Bot h o fth e abov

e formulas , (1 ) an d (2) , ca n be expresse d withou t th e FPC , yTTT^j

. whethe ro rno t th e FP C i s used , depend s upo n wha t yo u ar e tryin g t o estimate
.

FINIT E POPULATION

CORRECTION

COEFFICIEN T Fo r eac ho f th e comparison s whic hfollow , precisio ni s compute dintwo ways : wit han

dwithou t th e finit e populatio ncorrectio ncoefficien t (FPC) . Th e FP C i s use dwhe nyo uwan t t o know th e confidenc e interva l abou t th e tru e mea nfo r a specifi c tim e perio dwit ha finit e numbe r o f possibl e observations . I f th e tim e period , o

nth e othe r hand , i s a sampl e take n fro m a muc hlarge r population , the nth e FP C i s no t used . Fo r example , sa y youwan t t o kno

w th e confidenc e interva l abou t th e tru e monthl y mea nfo r Novembe r 198 5 a t a site . Ther e ar e onl y 3 0 possibl e sampling day s i nth e mont ho f November . T o tak e thi s facto r int o account , th e FP C i s used . I f every day i s sampled , th e tru e mea nfo r thi s particula r Novembe r 198 5 woul dP. 4

maximu m quarterl y

average s below

th e standar dar e upwindsite s o f lea d sources , whil e th e coefficient s o f variatio nfo r th e sourc e site s wit h maximu m quarterl y

average s abov e th e standar dar e downwindsite s o f lead source s an

dar e bein g Impacte dt o a greate r degre e b y th e source . I

nbot h cases , i t 1 s assume dtha t thes e coefficient s o f variatio nwil l b e indicativ e o f futur e coefficient s o f variatio na s th e sourc e come s int o compliance . Thi s assumptio nma y

b e overl y

conservative . Th e coefficient s o f variatio n fo r source-oriente dsites , wit hhighe r concentrations , ma y decreas e and resembl e thos e wit hlowe r concentrations , a s th e sourc e come s int o compliance . Inan y event , thes e tw

o type s o f source-oriente dsite s ca nprovid e a bound onwher e th e precisio nassociate dwit hfutur e source-oriente dsite s ma y li e a s th e sourc e come s int o compliance . RESULT S Table s 4 , 5 , 6 , an d 7 ar e structure d i n th e sam e way . The firs t colum n indicate s ho

wmuc h informatio n i s bein g use d - 1 versu s 3 years . Th e secon d colum n indicate s th e samplin g plan : E 6 (7 5 percent ) represent s everysixt h da

ysamplin g wit h 7 5 percen t dat a capture , E 6 represent s every sixt h da ysamplin g wit h 100 percen t dat a captur e an d s o on . The samplin g increase s fro m every

sixt h da

y(E6 ) t o everythir d da y(E3 ) t o everyothe r da y(E2 ) t o everyda

y(ED)
. The thir d an d fourt h column s summariz e precisio n accordin g t o th e amount o finformatio n use d - 1 yea rversu s 3 years , an d th e samplin g pla n fo rth e monthl yaveragin g time
. The thir d colum n labeled , FP

C PERCEN

TO F MEAN , list s th e precisio n calculation s usin g formul a 2
. The fourt h colum n labelled , W O - FP C PERCEN

TO F MEAN , recompute s th e precisio n calculatio n i n formul a 2 withou t th e FPC , ' V i - ^/^

. The calculatio n usin g th e FP C (column s 3 an d 5 ) assumes tha t samplin g i s takin g plac e fro m a finit e population , whil e th e precisio n estimate s i n column s 4 an d 6 assume tha t samplin g i s takin g plac e fro m a n infinit e population
. Th e fift h an d sixt h column s summariz e precisio n accordin g t o th e amount o finformatio n use d - 1 yea rversu s 3 years , an d th e samplin g pla n fo rth e quarterl yaveragin g time
. Th e fift h colum n compute s th e precisio n estimate s wit h th e FPC , whil e th e sixt h colum n compute s th e precisio n estimate s withou t th e FPC

. A s on e woul d expect , Table s 4 , 5 , 6 , an d 7 al l sugges t tha t th e precisio n associate d wit h th e quarterl ymea n i s tighte rtha n th e precisio n associate d wit h th e monthl ymean . Further , th e precisio n associate d wit h 3 year s o f informatio n i s tighte rtha n th e precisio n associate d wit h 1 yea ro finformation
. Finally , th e precisio n calculate d usin g th e FP C i s tighte rtha n th e precisio n calculate d withou t th e FPC , as woul d be expected
. CONCLUSION

S I n selectin g criteri a fo ra n ai rqualit ystandard , 3 year s o f informatio n wil l provid e tighte restimate s o fprecisio n tha n 1 yea ro f information , as woul d be expected
. Further , th e quarterl yaveragin g tim e i s preferabl e t o th e monthl yaveragin g tim e i n orde rt o achiev e tighte r precision
. A

n examinatio n o fTable s 4 throug h 7 indicate s tha t th e require d samplin g coul d var yaccordin g t o th e sit e type
. Usin g th e genera l rule ,P. 5

tha t 1 t woul d b e desirabl e t o hav e th e tru e arithmeti cquarterl ymea n b e withi n _ + 1 0 percen t o fth e sampl e arithmeti cquarterl ymean , 95 percen t o f th e time , th e followin g observation s ca n b e made : Wit h th e FPC :
° Fo r sourc e oriente dsite s wit hmaximu m quarterl y

average s les s thanth e curren t standard , th e sampling frequenc y woul dhav e t o b e increase dt o every othe r da

y sampling (Tabl e 5) . 0 Fo r source-oriente dwit hmaximu m quarterl y

average s greate r thanth e curren t standard , th e sampling frequenc y woul dhav e t o b e Increase dt o every da y sampling (Tabl e 6) . ° Fo r th e NAM S maximu m urbanconcentratio nsites , th e sampling frequenc y woul dhave t o b e increase dt o every thir dda

y sampling (Tabl e 7) . Withou t th e FPC :
° Fo rsource-oriente d site s wit h maximu m quarterl yaverage s les s tha n th e curren t standard , th e samplin g frequenc ywoul d hav e t o be Increase d t o ever yda

ysamplin g (Tabl e 5)
. o Fo rsource-oriente d site s wit h maximu m quarterl yaverage s greate rtha n th e curren t standard , th e "samplin g frequenc ywoul d hav e t o be increase d t o every da ysamplin g (Tabl e 6)
. Eve n wit h everyda ysamplin g fo rth e 3 quarter s i n th e specifi c3 yea rtim e period , precisio n o f+ 1 0 percen t coul d no t be achieved
. Keep i n min d tha t th e 3 quarter s o 7 dat a ove rth e specifi c3 yea rperio d i s treate d as a complet e sampl e o fa "typical " 3-yea rperiod , draw n fro m th e populatio n o fal l possibl e 3-yea rperiods , and , as such , th e FP

C i s no t used
. 0 Fo rth e NAM

S maximu m urba n concentratio n sites , th e samplin g frequenc y woul d hav

e t o be increase d t o everyothe rda y(Tabl e 7)
. I n conclusion , th e us e o fth e FP C i s appropriat e i n makin g inference s abou t pas t events , bu t i t i s probabl yno t appropriat e fo rexpecte d events
. Th e samplin g frequency , discusse d above , i s intende d t o appl yt o monitorin g site s nea rth e standar d level
. A s ambien t lea d level s approac h th e standard , th e variabilit yi n th e ambien t lea d dat a ma ydecrease
. Therefore , th e samplin g requirement s coul d probabl yb e relaxed
. REFERENCE

S 1
. A
. D
. Thrall , J
. L
. Baptlst a an d C

. S

. Burton , Fina l Report , An Examinatio n o fAi rQualit yDat a Completenes s Requirements , System s Applications , Inc
. Prepare d fo rMonitorin g an d Dat a Analysi s Division , Offic e o fAi rQualit yPlannin g an d Standards , U
. S

. Environmenta l Protectio n Agency , Researc h Triangl e Park , N.C , Ma y1984
.P. 6

2 . G . Yarn , U . S . Environmenta l Protectio n Agency , "Sourc e Oriente d A1 rQualit yMonitor s fo rLead, " lette rt o Eri c Goldstein , Natura l Resource s Defens e Council , Marc h 5 , 1985 . 

### Attachment s cc : R . Rhoads (MD-14 ) J . O'Conno r(MD-12 ) B . Jorda n (MD-12 ) J . Cohen (MD-12 ) D . Sledg e (MD-12 )Tabl e 1
. Lis t o fSource-Oriente d Site s wit h Maximu m Quarterl yLead Average s Les s tha

nth e Standar

d

Sit e Locatio

n
030240004F0 1 Douglas , AZ 101800082G0 2 Hillsbor o Co. , F

L 130840006F0 2 Kellog , I D 151180001H0 2 E . Chicago , I N 151180004H0 2 E . Chicago , I N 243300046F0 2 St . Paul , M N 390720717F0 2 Berk s Co. , P A 491840057A0 2 Seattle , W A Composit e Avg . C.V.' s Source Type * 

### PC S SL S PL S I S I S LO M SL S SL S n 8 15 15 9 10 1 4 1 2 8 QUARTERL

Y Av g S.D . 0.3 1 0.2 3 0.3 9 0.7 1 0.7 9 0.2 5 0.4 0 0.7 3 0.1 9

0.1 5 0.5 7 0.7 4 0.8 0 0.1 8 0.3 3 0.3 8 

### CV .

0.6 1 0.6 5 1.4 6 1.0 4 1.0 1 0.7 2 0.8 3 0.5 2 

### n

3 4 5 3 5 5 5 3 MONTHL

Y Avg . S.D . 0.4 4 0.3 3 0.8 5 1.5 8 1.0 6 0.4 2 0.6 0 0.7 2 0.2 6

0.2 6 0.7 9 0.6 9 1.0 6 0.1 7 0.3 8 0.5 4 C V .

0.5 9 0.7 9 0.9 3 0.4 4 1.0 0 0.4 0 0.6 3 0.7 5 0.8 6 0.6 9

* LO M = Lea dOxid e Manufacturer PC S = Primar

y Copper Smelter PL S = Primar

y Lea dSmelter I S = Iro

nan dSteel Plan

t SL S = Secondar

y Lea dSmelterTabl e 2 . Lis t o f Source-Oriente dSite s wit hMaximu m Quarterl y

Lea d Average s Greate r thanthe Standar d(1. 5 ug/m3 )

Sit e Locatio n
012140004G0 2 Leeds , A L 013240003F0 2 Troy , A L 131420021F0 2 Shoshon e Co. , I D 142960010F0 1 Granit e City , IL 151780011F0 5 Hammond , I N 243300038F0 1 St . Paul , M N 262280011J0 5 Jefferso nCo. , M O 270860002F0 2 Lewi s & Clar kCo. ; Composit e Avg . C.V.' s 

### M T Source Type * SL S SL S PL S SL S LO M LO M PL S PL S n 1 5 1 5 1 4 1 3 1 5 1 0 1 5 26 QUARTERL

Y Av g S.D . 3.0 4 7.0 8 1.7 5 1.5 4 2.7 3 7.9 7 6.7 0 3.8 6 2.6 4

9.4 9 2.0 5 1.8 3 5.1 6 16.8 1 12.4 5 2.8 9 CV .

0.8 7 1.3 4 1.1 7 1.1 9 1.8 9 2.1 1 1.8 6 0.7 5 n

5 5 4 6 5 3 5 9 MONTHL

Y Avg . S.D . 4.6 6 13.0 7 2.7 5 2.0 2 6.1 5 6.1 3 11.8 5 4.3 9 3.2 2

14.6 1 3.4 2 2.4 7 8.1 5 5.3 5 19.1 7 2.8 5 CV .

0.6 9 1.1 2 1.2 4 1.2 2 1.3 3 0.8 7 1.6 2 0.6 5 1.4 0 1.0 9

* LO M = Lea dOxid e Manufacture r PC S = Primary

Coppe r Smelte r PL S = Primar y

Lea dSmelte r I S = Iro

nan dStee l Plan t SL S = Secondar y

Lea dSmelte rP. 9

Tabl e 3 . Lis t o f Nationa l Ai r Monitorin g Station s (NAMS ) Use dt o Determin e

th e Monthl y

an dQuarterl y

Coefficient s o f Variatio nfor th e Maximu m Urba nConcentratio nSites . NAM S SIT E QUARTERL YMONTHL Y No . o f Std . Locatio nObsn(s ) Avg . Dev . CV . 056400003F0 1 Riverside , C A 1 1 0.6 9 0.3 2 0.4 6 05716000110 1 SanRafael , CA 1 6 0.5 5 0.2 3 0.4 2 191870003F0 1 Jefferso nParrish , 1 1 0.4 2 0.2 6 0.6 2

L A 261040002G0 1 St . Loui s Co. , M O1 6 0.5 1 0.4 0 0.7 8 330660017F0 1 Buffalo , N Y1 0 0.8 5 0.6 0 0.7 1 334680052F0 1 New

Yor kCity , N

Y1 2 0.9 2 0.2 9 0.3 2 442340035G0 1 Memphis , T N 1 4 1.4 1 0.7 5 0.5 3 451880023F0 1 For t Worth , T X1 5 0.9 0 0.6 2 0.6 9 COMPOSIT E AVERAG E C.V.' s 0.5 7 0.5 0 No . o f Obsn(s ) 5 6 4 5 6 4 4 5 Avg . 0.7 6 0.5 7 0.4 4 0.7 9 0.6 9 0.9 3 2.1 0 1.0 5 Std . Dev . 0.3 7 0.2 6 0.2 6 0.5 8 0.4 3 0.4 1 1.0 3 0.1 9 C V .

0.4 9 0.4 6 0.5 9 0.7 3 0.6 2 0.4 4 0.4 9 0.1 8P.1 0

Tabl e 4 . Compariso n o fConfidence Interval s fo rAlternativ e Samplin g

Plan s fo rMonthl yand Quarterl yArithmeti c Mean s fo rAl l Sites .

1 1 PtKIUl J 1

» 1 MT H 1 UT H | 1 IFP C - XU F IrtU.FP C - XIFP C - XO F l.tll_FP C - X1 1 1 MEA N 1 O F MEA M 1 MEA N 1 O F MEA N 1 ITIM & PERIO D (PLA N 1 1 1 1 I I t YEA « lE b (7SX ) * | 87.U l 93.9 i 3«,9 I 37.5 1 1 IE 6 1 66.V I 73.2 1 29.8 1 32.7 1 1 IE 3 175 * j 1 12.2 1 *»9,3 I 21.3 1 2«.<* l 1 IE 3 1 3<4.5 I "2.2 1 1 to. 0 1 22.o | 1 l£ 2 (75X ) 1 2V.0 I 37.5 1 15.5 1 20.0 1 1 IE 2 1 23.i l 32.7 1 12.5 1 17.7 1 1 IE U (75X ) 1 11.1 1 2«.'V I 6.2 1 13." 1 1 "*

' IE U 1 0.0 1 22.I' I O.O i 12.« l l i rtA* 3 IPLA N 1 1 1 1 1 1 IE 6 (75X ) 1 3«.9 I 37.5 1 18.6 1 20.0 1 1 lE b 1 29.8 1 32.7 1 16.1 1 17.7 1 1 IE 3 C7SX ) 1 21.3 1 2«.V I 11.9 1 13.9 1 1 IE 3 1 Id.0 1 . 22.0 1 lu.l l 12.0 1 1 IE 2 (7SX ) 1 15.5 1 20.0 1 8.7 1 11.3 1 1 IE 2 1 12.5 1 17.7 1 7.1 1 10.l l 1 IE U 175X ) 1 6.2 1 13.9 1 3.6 1 8.0 | 1 IE U 1 0.0 1 12.1 1 O.O I 7.1 1P.1 1

Tabl e 5 . Compariso n o fConfidence Interval s fo rAlternativ e Samplin g

Plan s fo rMonthl yand Quarterl yArithmeti c Mean s fo rSource Oriente d Site s wit h Maximu m Quarterl yAverages Les s tha n th e Standard . PfcWIU U MT M Wl K IFP C - XU F l*0_FP C - XIFP C » XU F IwU.FP C - X I MEA N

I O F MEA N

| MEA N

I (I

F MEA N TIMf c PEK1U Q IPIA N

» Vfc* K IE 6 (7SX ) I 102.2 1 I

1U9.8 I I

50.9 1 So.o i I — _L£6
_ I........ . IE 3 t75X ) J-lmAmiL 49.4 1 57.7 1 3 1
. H 47.6 1 36.3 1 I — IE 3 T - i —— - I E 2 175X ) 40.3 1 19,4 1 26.2 1

IE 2 3i.u l I - IE U (75X J 27.0 1 43.B l 36.2 1 22.5 1

lb.<j l I--
. IE U \1A9.±. 29,1L „
>t.... « I PLA N O.O I .2S.«I. . .....f . I o.o i 32.1 1 29, 1 25.8 1 20.2 1 18.0 1 i rtAK S l '

IE 6 (75X ) I — l E b 40.8 1
I........ . I E 3 175X ) mh.m.V-m 25.0 1 43.* l

36.2 1 27.1 1

23.5 1 I — IE 3 I E 2 175X ) _21**L L miHimllL. 2 b , 8J
_ 17.3 1

I— • IE 2 16.1 1 I ' 14.6 1 2it*! . 12. 7 1

IE U (75X ) IE U 10.4 1
0.0 * A5** L

14.5 1 b.2 l

( I
. 0 I 29.1 1

25.H I 20.2 1
>»•» ' 16.4 1 l»l " 11.6 1 10.4 1P.1 2

1 t V Tabl e 6 . Compariso n o fConfidence Interval s fo rAlternativ e Samplin g Plan s fo rMonthl yand Quarterl yArithmeti c Mean s fo rSource Oriente d Site s wit h Maximu m Quarterl yAverages Greate rtha n th e Standard .

1 1 PEHiO U 1 1 1 MT H 1 UT K1

•IFP C - XU F IhO.FP C - XIFP C - XU F MO_FP C - X1 1 1 MEA N 1 U F MEA N | MEA N 1 O F MEA N | IT1M E PfcKIU O IPLA N 1 1 1 1 I 1 1 YEA H lE b (7SX ) 1 161.4 1 173.4 1 82.0 1 89.0 1 1 It o 1 123.5 1 135.3 1 7o.b l 77.5 1 1 IE 3 175X > 1 76.0 1 91.1 1 Su.o i S9 f1 | 1 IE 3 1 63,7 1 70.0 1 42.7 1 S2.3 I 1 IE 2 (75X ) 1 53.6 1 e9.3 l 36.7 1 47.4 1 1 IE 2 1 4*.7 1 60.4 1 29.7 1 41.9 1 1 IE U 175X J 1 20.6 1 46.0 1 14./ | 32.9 1 1 IE U 1 O.o i 40.7 1 O.O I 29.3 1 1 3 YfcAH S IPLA N 1 1 1 1 1 1 lE b l75X ) 1 64.5 1 oV.J I 44.1 1 47.4 | 1 lE o 1 55.1 1 60.4 1 36.3 * 41.9 | 1 IE 3 175 U 1 39,4 1 46,0 1 28.2 1 32.9 | 1 IE 3 1 33.2 1 40.7 1 24.u l 29.3 1 1 IE 2 175X ) 1 20.6 1 3o,V | 20.7 1 26.7 1 1 IE 2 1 23.1 1 32.7 1 16.9 1 23.9 1 1 Ifc u (75X J 1 11,5 1 25.o | 8.5 1 18.9 | 1 IE U 1 O.o i 22.1 1 o.\) l lo.9 lP.1 3

Tabl e 7 . Compariso n o fConfidence Interval s fo rAlternativ e Samplin g Plan s

fo rMonthl yand Quarterl yArithmeti c Mean s fo rNAM

S Maximu m Urba n Concentratio n Sites .

PtHiU U MT M UT H IFP C - XU F IrtO.FP C - XIFP C - XU F IwU.FP C - X J ME> NI (I

P MEA N| MEA

N I O F MgA N TJMt , PfcHlUQ "»LA N J
_ _ L 1 YEA N tE O C7SX J I .UUl-L I

79.5 ' I

33.7 1 _ib^ £ I — lE o .....t . S b t 7 l o2. 1 I ?«.« ' at.f c IE 3 t7SX J 35.8 1 41.6 1 20.6 1 24- 1 I — g9.g | iS.H I .«•• •+ . 17.4 ' 21. 3 i I E 2 175* ) 2^.6 1 ..-.1-JLL- JJL.9J
_ 19. 3 I.. . ALi
. 19.b l ^7. 7 I 12.1 ' 17. 1 i IE U C75X ) I — . IE U mlmdmlm . o.o i 21.1 1 6 . 0 1

•+.... . I P L a n 10.7 1 p....f . o.o i M. " 11. 9 3 YEAK S I lE o C7SX ) I-- . lE o I g*<.O l I

-UL**L . I

lo.o ' .Hill ^l*T± ji.^ J |

. ....... . ' £ i C75X J lb.l l til.I I U.* l 19. 3 17. 1 13. 4 I IE 3 I........ . I E 2 175X ) 15.2 1 ..... t . A«*L L 9.8 1
I — I t 2 13.1 1 lo.b l 16.9 1

15.0 1 6.4 1

b.9 l _Ll ^

10. 9 9 . 7 _Lku
. LZ*?A_

_ lE u J>.A L

»». •SL L .10.5 1 3.4| . <>.l " _L* 1

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