```
str(cake)
## 'temp' is continuous, 'temperature' an ordered factor with 6 levels
(fm1 <- lmer(angle ~ recipe * temperature + (1|recipe:replicate), cake, REML= FALSE))
(fm2 <- lmer(angle ~ recipe + temperature + (1|recipe:replicate), cake, REML= FALSE))
(fm3 <- lmer(angle ~ recipe + temp + (1|recipe:replicate), cake, REML= FALSE))
## and now "choose" :
anova(fm3, fm2, fm1)
```

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