JIHER EXPERIMENTAL DESIGNS

je highly correlated
ce of these correla-
sides in the number
ne and effort to test
int here is that the
e use of repeated-
ents with repeated
nts may affect per-
r fatigue, practice,
from such circum-
vestigator may not
under the different
 carry-over effects.
ut designs in the as-
1sual assumption of
' is made regarding
ed in some detail in

EMENTS:
RES

or experiment with
f numbers in which
zresent treatments;
at for the two-way
sis of such data in-
two-way classifica-
d computation for-
res result: sums of
nteraction.

urements, subjects
y viewed as fixed.
ations of the mean

veen treatments is
ividual differences

ve m ozki

a ih PSA OPARA oa ZGAGA v kd dj Šarm

man inten

Cie
Ze da m Drva RA Pari sol ŠA oi a

žo Ta SANA ČALA o A čo

nobe d 3t MRNi7RDAE VE smr se

a aa 4e

19.4 ILLUSTRATIVE EXAMPLE OF ONE-FACTOR EXPERIMENT WITH REPEATED MEASUREMENTS 307

19.4

between subjects is possible, unless it is assumed that the interaction term
is0. With nearly all sets of data this assumption is not warranted, because
the performance of subjects under different pairs of treatments is corre-
lated. Ordinarily in most experiments of this type individual differences
between subjects are of limited interest anyway, because with most vari-
ables that are the object of study the investigator expects a priori substan-
tial differences between subjects.

ILLUSTRATIVE EXAMPLE OF ONE-FACTOR
EXPERIMENT WITH REPEATED MEASUREMENTS

Table 19.1 shows hypothetical data for a one-factor experiment with re-
peated measurements. Rows are individuals, and columns are treatments.
The data are presumed to relate to a random sample of individuals tested
under different treatment conditions. This is a mixed model. One basis of
classification, the columns, is fixed. The other basis of classification, the
TOws, is random.

———i iin —ieiv—mvm dove m m v cv
Table 19.1

Data for the analysis of variance with two-way classification: z —1,
scores for a sample of subjects tested under four difterent conditions

Conditions

Subject A B c D T,. X,.
——o ov gv vv v -
1 31 42 14 80 167 41.75

2 42 26 25 106 199 49.75

3 84 21 19 83 207 S1.75

4 26 60 36 69 191 47.75

5 4 35 44 48 141 35.25

6 16 80 28 76 200 50.00

7 29 49 80 39 197 49.25

8 32 38 76 84 230 S7.50

9 45 65 15 91 216 54.00

10 30 71 82 39 222 s5.50
——o sor v v vv. , —.v,c-
T, 349 487 419 715 T< 1,970
X. 34.90 48.70 41.90 7.50 X. — 49.25

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>, T,? — 394,350 B T,'— 1.045,756 y y X reč — 122,984

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