> caffeine1.rbd <- aov(endtime ~ subject_c + dose_c)
> 
> summary(caffeine1.rbd)
            Df Sum Sq Mean Sq F value    Pr(>F)    
subject_c    8 5558.0  694.75 13.2159 4.174e-07 ***
dose_c       3  933.1  311.04  5.9168  0.003591 ** 
Residuals   24 1261.7   52.57                      
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 
> 
> interaction.plot(subject_c,dose_c,endtime)
> 
> caffeine.res <- residuals(caffeine1.rbd)
> 
> hist(caffeine.res)