{

}

This is the plot of group size over time.

There is a periodical pattern on the group size. Every three weeks, the group size become smaller than usual. On the yearly basis, the group size is getting smaller.

The plot shows the mean score and mean rate for different group.

Since mean score is the higher the better and mean rate is the lower the better, the points close to the upper left corner are the better. Clearly, group A performs better than group B and C.