Tukey’s Honest Significant Difference tests

For assays in which putative repellent treatments were presented in the T-maze olfactometer with or without citrus and versus clean air, the number of Diaphorina citri remaining at the release point and not entering the olfactometer was compared between treatments using one-way analysis of variance, followed by Tukey s honest significant difference test (p <. 05). For psyllids leaving the release arm, the number of psyllids choosing the control arm versus the treatment arm was compared with chi-square (/ ) analysis at p <. 05. The data from all four replicates were combined for the analysis. 

Bonferroni s test is overly conservative, in that the critical values required for rejection need not be as large as they are. In other words, using a less conservative method may result in more null hypotheses being rejected. The reason that Bonferroni s method is so conservative is that it does not in any way account for the extent of correlation among the various hypotheses being tested. If a method could take into account the overlap, or lack thereof, of the various hypotheses, the critical values would not need to be defined as narrowly as with Bonferroni s. In this section, we therefore discuss another analytical strategy for multiple comparisons, Tukey s honestly significant difference (HSD) test. 

Statistical calculations were carried out using Stata 8 (Stata Corp LP 2005) as a program to analyze data. To verify the homogeneity of variance, the Barlett test was applied, then One-way analysis of Variance (ANOVA) was performed, and significant differences (P < 0.05) among samples were determined with Tukey s honestly significant difference range. 

The Student s t-Test was used to assess the statistical significance of the differences between the resistances at the different frequencies, on the different points. To assess the differences between data of the four groups of patients in the sample (colitis, diverticulosis, polyps and normal), we used the Multiple Range Test with Tukey HSD (honest significant difference). 

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