Difference between Tukey, Tukey b and Tukey HSD

[Indranil Dutta]

Could any one let me know what the difference between these post-hoc
tests are?

Thanks

[Ray Koopman]

Indranil Dutta wrote:
> Could any one let me know what the difference between these post-hoc
> tests are?

They are all for pairwise comparisons of the means of k independent
equal-n groups. They give the rule for choosing the critical value
of q = (Mi - Mj)/sqrt(MSE/n) from the studentized range table.

Tukey = Tukey a = Tukey HSD = Honestly Significant Difference:
always use the value in column k.

Tukey b = Tukey WSD = Wholly Significant Difference:
use the average of the values in columns r and k, where r is
conventionally (but wrongly, IMO) called "the number of steps apart"
that the ordered means are (2 <= r <= k; the Newman-Keuls test always
uses the value in column r).