Hi everyone,

Apologies if this is a silly question but I am a student and this is my first time using R so I am still trying to educate myself on commands, models e.t.c



I run an experiment were I wanted to explore the effects of four dichotomous factors on a dependent variable. Participants completed 4 vignettes each with factors crossed across vignettes. As I can't treat each response as separate because it is nested within the subject, I was going to use a mixed model with the factors/IV's as the fixed effects and Subject as the random effect.



I used the lme4 package and the following formula;



modela <- lmer (DV ~ IV*IV*IV*IV + Covariate + Covariate + Covariate + (1|Subject))

anova(modela)



I then obtained p values to check the significance using the Markov-chain Monte Carlo formula;


print(pvals.fnc(modela,addPlot=FALSE))


When I looked at the p values some are showing as significant although the F values are less than 1. Is it possible to have a significant effect with an F value below 1?.

I have a sample size of 150 and have read that the pMCMC values can be anti-conservative so wonder if it is because my sample size may be too small?.

Thank you for any help.

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