Exploration and description

We need to check other analysis of variance assumptions.

By rerunning the analysis of variance and then clicking Options on the GenStat screen and then Residual Plots... we obtain the graphs alongside.

We can see that the distribution is a little scattered, though essentially normal and that the residual values tend to increase with increasing size of observation. This reflects the differences in variation between planting dates 1 and 2 and planting date 3 observed earlier.

However, the normal plots are reasonably linear at 45^o, and so we shall show the results of analysis of variance based on the raw data.