CONSEQUENCES OF VIOLATING THE INDEPENDENCE ASSUMPTION IN ANALYSIS OF VARIANCE
CONSEQUENCES OF VIOLATING THE INDEPENDENCE ASSUMPTION IN ANALYSIS OF VARIANCE
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DOI:
10.1037/0033-2909.99.3.422
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发表时间:
1986-05-01
影响因子:
22.4
通讯作者:
JUDD, CM
中科院分区:
文献类型:
--
作者:
KENNY, DA;JUDD, CM
The purpose of this article is to present a comprehensive discussion of the biasing effects of nonindependence of observations on the mean squares used to test the effect of some discrete independent variable. We start by defining nonindependence of observations and discuss three commonly assumed patterns of nonindependence : nonindependence due to groups, nonindependence due to sequence, and nonindependence due to space. We then show how the bias in both the mean square for treatment and the mean square for error can be derived when each of the three patterns of nonindependence is ignored in analyzing the effect of a discrete independent variable. In each case we show that the bias introduced can be considerable. Further, the combined effects of the bias in each of the mean squares can lead to either too large or too small F ratios. We briefly discuss ways to eliminate the biases, either by including the source of nonindependence in the analysis, transforming the data to remove it, or modeling it. Finally, we suggest that nonindependence of observations should be looked at not simply as a statistical nuisance, but also as a substantive issue central to many areas of psychological research.