ERIC Number: ED357078
Record Type: Non-Journal
Publication Date: 1993-Apr
Reference Count: N/A
Nonparametric Test of Ordered Alternatives: Extension of Page's L Test for Two Groups of Unequal Size.
Beasley, T. Mark; Leitner, Dennis W.
The L statistic of E. B. Page (1963) tests the agreement of a single group of judges with an a priori ordering of alternative treatments. This paper extends the two group test of D. W. Leitner and C. M. Dayton (1976), an extension of the L test, to analyze difference in consensus between two unequally sized groups of judges. Exact critical values are tabulated for small numbers of treatments and judges, and a unit normal approximation is developed for larger samples. A brief computation example is also provided. Analysis of the two-tailed unit normal approximation shows that disparity between sample sizes often leads to underestimating the probability of a Type I error. However, as the number of treatments increases, the fit becomes better. This test, in comparison to two parametric competitors in a 2 by 4 mixed design, made fewer Type I errors when data were sampled from the normal, uniform, and exponential distribution, but it was also shown to be generally more conservative. The unit normal approximation is not severely affected by unequally sized groups having heterogeneous variances. The proposed test shows adequate power in conditions that do not favor parametric tests (i.e., interval level, normally distributed variables). Four tables present analysis results, and four figures illustrate the discussion. (SLD)
Publication Type: Reports - Evaluative; Speeches/Meeting Papers
Education Level: N/A
Authoring Institution: N/A