[R-lang] question about model interpretation using lmer

[Schack Tang, Katie]

Hi,

I have a question about interpreting a mixed effects model.  I am modeling median F0 on a vowel based on a variety of factors.  The one I am concerned with here, PrecedingSegment, has 6 levels.  I give the R output from a lmer function below.

PrecSegment(none)	-1.716815	4.3652	0.393
PrecSegment(son)	  3.488424	0.919801	3.793
PrecSegment(vce)  	0.745261	0.948666	0.786
PrecSegment(vceless)	7.233391	0.928507	7.79
PrecSegment(vowel)	8.319552	4.782556	1.74

The withheld value is implosive.

I have two questions:

1) Does the fact that voiced (vce) fails to reach significance on its own indicate that its effect on F0 is not significantly different from the effect of an implosive on F0?
2) What can I conclude about the sonorant (son) and voiceless (vceless)?  Can I just conclude that they both raise F0 compared to implosives?  Or can I also conclude that voiceless raises F0 more than sonorant does?  If the former, how can I test the latter--is it possible to specify which level of a factor is withheld in lmer?

Thanks,


Katie Tang
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