| department of population ecology | ::: | institute | ::: | university | ::: |  |
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dr hab. Mariusz Cichoń
cichon@eko.uj.edu.pl |
Dep. of Population Ecology Inst. of Environmental Sciences Jagiellonian University Gronostajowa 7, 30-387 Kraków Poland tel. + 48 12 664 52 01 fax + 48 12 664 69 12 |
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Cichoń M., Merilä J., Hillström L., Wiggins D.
OIKOS
1999; 87 (1): 191-194
Abstract:
An assumption central to many tests of statistical association between two variables is the null-expectation of zero association. Here, we draw attention to the fact that in many published tests of mass-dependent mass loss in breeding birds, this assumption has been violated. We show that a correct null-hypothesis can be derived by using resampling methods, and analyse three data sets (two previously published) from passerine birds to illustrate the approach. Our results show, that under a correct null-hypothesis, the biological interpretation of the previously published results is reversed - initially heavy birds do actually loose less mass (relative to their weight) than the initially light birds.
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