[R] Heteroscedastic data due to responses at one factor level being too low to measure and assumed to be 0?

Hello all, I have a 3-factor experimental design. The response is the load to break an adhesive joint. I have a question about Heteroscedastic data ('non-uniform variability', Google told me that's what it's called - I'm not a statistician, just an engineer) *In essence:* - At one level of a

Re: [R] leveneTest between 2-levels of 3-level factor in R?

#x27;Cryst')[,5], subset(results,ADHES == 'Poly'|ADHES == 'Cryst')[,3]) which gives the same results as your suggestion, which I can now look into how it works many thanks. Leigh On 19 October 2015 at 22:13, Rolf Turner wrote: > On 20/10/15 01:02

[R] leveneTest between 2-levels of 3-level factor in R?

Still feeling my way around using R... What I have done so far: I have a data.frame 'results' with response 'Fail', and three factors 'PREP', 'CLEAN' & 'ADHES'. ADHES has 3 levels: Crest Cryst Poly I calculated the variances: sigma..k=tapply(Fail,ADHES,var) print(sqrt(sigma..k)): CrestCrys