For checking the model assumptions, use the following residual plots: (i) plot ri versus ŷi , (ii) plot ri versus xi , (iii) plot ri versus time sequence i, (iv) plot ri from replicates grouped by...

For checking the model assumptions, use the following residual plots:

(i) plot ri versus ŷi

,

(ii) plot ri versus xi

,

(iii) plot ri versus time sequence i,

(iv) plot ri from replicates grouped by treatment.

If any of these plots shows a systematic pattern, one or more of the model

assumptions are violated. Countermeasures should be taken. If there is a large

number of replicates per treatment, a box-whisker plot is recommended. It

enables the location, dispersion, skewness, and extreme values of the replicated

observations to be visually compared.