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Chapter 9: Field Intercomparison
Table 9.2: A comparison of the power of several scalar and multivariate tests
in the case of two types of spatial correlation structure. The scalar tests look
for departures from the null hypothesis in the direction of the first EOF, in
the direction of the true departure J.lo from the null hypothesis and in the
direction of v of maximum power. The multivariate tests are pp /D 2 and an
exact chi-square test. Power of multivariate tests with independent variables
are indicated in brackets. (From, Zwiers, 1987).
Spatial
Scalar test
Multivariate test
correlation
m First
J.lo
v
PP/D 2
X 2
structure
EOF
Geographically 2
0.31
0.31
0.31
0.25 [0.3Ol 0.24 ~0.42]
expanding
4
0.36
0.36
0.54
0.29 [0.63] 0.34 [0.60]
network
8
0.48
0.60
0.83
0.34 [0.83] 0.51 [0.83]
12 0.05
0.88
0.95
0.57 [0.87] 0.63 [0.94]
24 0.05 >0.99 >0.99 0.77 [1.00] 0.86 [0.99]
Network with
2
0.42
0.42
0.42
0.33
0.33
increasing
4
0.48
0.48
0.50
0.42
0.31
density
8
0.49
0.51
0.54
0.38
0.25
12 0.50
0.51
0.55
0.45
0.22
24 0.50
0.51
0.56
0.46
0.20