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Suppose I have following results from my 2 experiments that contain 3 Block each and there are 4 treatments per Block (the example is R based)

dft <- data.frame(Exp = rep(1:2, each = 12), 
                 Block = rep(rep(1:3, each = 4), each = 2), 
                 Treat = rep(1:4, 6), 
                 Plot = rep(1:12, 2),
                 y = rnorm(24, mean = 10, sd = 2))

I want to find out if there are differences between Treat and Exp. I used folowing model

library(nlme)
myMod <- lme(y ~ Exp*Treat, random = ~1|Block/Plot, data = dft, method = "ML")

but I got the comment that I should include Block nested in Exp in my model I did that too

myMod1 <- lme(y ~ Exp/Block + Exp*Treat, random = ~1|Block/Plot, data = dft, method = "ML")

and than compare both models which were not significantly different

anova(myMod, myMod1)

if there are no differences which model is more logical in this case???

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  • $\begingroup$ The simplest one. $\endgroup$ – user2974951 Feb 5 '19 at 8:38
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The principle of Occam's Razor, or model parsimony, would apply here. Given two models with similar results, we should prefer the simpler one.

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