Statistical modelling

Dry corm weight

We are now ready to carry out analyses of variance (Stats → Analysis of Variance ...). By clicking Options and adding a tick for %CV we find at the end of the output that the coefficient of variation for dry corm weight is 30.4%. This is rather large and possibly influenced by the conditions under which the experiment was conducted. Normally one would expect a value closer to 15% for a field experiment.

The output includes the analysis of variance which shows that there are no overall differences among landraces, nor does level of fertiliser have any effect on dry corm weight. However, date of planting has not only a highly significant effect overall but more importantly also a highly significant interaction with Landrace.