Philip has been unfortunate enough to get significance on his 4th and 5th
order trends, and is hoping that nonsignificance of the 3rd order trend
means the higher order trends are spurious. Sorry no. Consider a perfect
quadratic relationship -- there will be absolutely no linear component. I
wonder if one should even test for trends of an order that one could not
interpret. They will always be present in some magnitude, and, given
sufficient sample size, will be "significant." It might help to compute
eta-squared (divide the trend SS by the total SS) and then use that
statistic to decide whether you can dismiss the "significant trend" as
trivial in magnitude -- I have generally been able to do so when having
encountered such higher order trends that defy interpretation but meet our
criterion of statistical significance.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++++ Karl L. Wuensch, Department of Psychology, East Carolina University,
Greenville NC 27858-4353 Voice: 252-328-4102 Fax: 252-328-6283
[EMAIL PROTECTED] http://core.ecu.edu/psyc/wuenschk/klw.htm
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