A Note regarding Problems with Interaction and Varying Block Sizes in a Comparison of Endotracheal Tubes

Table 3

Least squares adjusted means for each type of tube using an additive model or an interaction model.

Dependent variables	Additive model		Interaction model
	Parker Flex-Tip	Standard ETT	Parker Flex-Tip	Standard ETT
Time for ETT insertion (sec)	10.8	12.3	12.0	11.1
Number of redirections	0.8	2.3	1.1	1.0
Difficulty of insertion rating	16.3	19.4	21.6	14.0

Note. The adjusted means were obtained using the General Linear Model ANOVA platform in Minitab V.16 and are the same as those obtained using PROC GLM in SAS V.9.3.