~-.~JiVIi~ s«M .

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tnad :x A) . In adflitim to PJese . otMr relevaat varia6les ~re
cvuidered for inclosim, hot a closer ammimum . of ttie :=
distribution ar .vs) cases and mrr`sols slwed no simuficant
diffelemcss. '.Tnse variaoles Kle : F]Wl1Rtl.'LV Dff= dR FJIli1LL .)^i:
tilFS 1aQf 8Ug5, T/C7G6 t7R 1U18M : 17UO6LN6 TO A rAS MOLQIf;
pAt .ro AT LLy£: rxMRE TO MEOS2E !1EP.TEFS : and M O6I7R . . 10 A 06V.
dp Wpp $Stllri (paqes 169 and
171 of AlpvidiII A) .
Ye believe trst au best djnnted vtL:etes ~e those cbtained
by rhe in-'-u+im of t
.he first qraQ of variables, since they are based
m the sret reliable inforsetam . In Me Mct chaprer, therefore, W
mly preseet Lir. additia : to t2r eude e+*lizatma1 the results of the
socalled 'Part'•lv ad7ustnant .
11 AtalI15I5
1Le e`nior of sutLstir,l amlysis terJniques rss primsrily
determire.d by the design of the stssly . 1hs latter called for the use
of terlniquea capable of aacou :ting for the srtOWsl, as .ell as for
tec`.niy+:es capable of dealing .ntb canolex situations in wuch
cv .araaces - in additian to the eq :osure verlables -- cnuld be taken
ssultaneauly into ca+sideratim .
3efore eVlaining amv f741y hae these technryves .ete eceLied .
Lt is Rr .ineet to rmtim that sinpler tetlmiq~e '.ere a'so _veG to
._r mpl :re :re :haracteristi6 of the data wlleaed. C:u.variace
http://legacy.library.ucsf.edu/tid/dsk94c00/pdf
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swtistics aed/or sisgle frequencies .ere nhea :n. . : for al~t all of
the variables for .R:ich ae had inforsettm . Such erplorarion of the
data also iacluded -- ..hen eproppriete - the ose of etem and leaf
or 6mo-ptot diegraee to m .e the nature of the distribirtim of
the varia6les, in both cases and co :trols . Il :e crapernhility of these
two qcapa also needed to be established and several sta~,ntiol tests
.ere perforsed to such an erd . In the ee.e of the variables that had
been used to perfcrm the art"'~ : ,4 IAiF. S7[ . 3pfTflC IQMIIIy .
P6IDQ1M AMD TYPE OF INitRVIDi/, wa Imm+ of moca that no
diffarersES ~e to be fosd . 9 :c there w no eertainty that cases
and cTtmis .eold he equal in otlrz rv-Apeers. 5ociodmoaraprtic
variv' les aoch as nw8er of ~s of snc=l attendsnam, kuaze, ethLLc
gnKp . oweRry of origie. rncEer of times s.rrid. and othe-^s . .wre
m:ns :ed osinq either paired t-tests fconti, ... . .s variaDlnl or ohi-
sqi:ere tests Ifttlser's test for dlcnttsaoum vsria6les or chi-equsre
for mteqcriml variables with sare than tuo lnalal . In the sene
faelum thone varf .bles that r_te viewd as potential cconfowd'Ys .ere
campsred first before deciding ylether or not to inclode thes as
cv+fouders in tLe final ansly .is. IM : apptioble, th mmerisom of
t.he petert .iaily m :faMieq v.riables +u done by treacinq the
variables as horh ®teqorifal Ifor efolnole . yee/no euoaure to gas
ccdu .?I and oas:irsoiu Ifor emmle . euo6sr of yesrs of empo,ure to
gas .cdanvl . 'Rxu . the decision to include a variable as cmfovicer
vas followed by the decisioe m .Aether to include it as a categorical
or as a emK.inunus vnriable . tagartic regrenioo ss used to
deternw:e if then w ev .denm to aswne linearity oa the effect of
the ?oc.ncial xnfousfer . It my be useful to advance enw that we