```
> average 1 groupby 2 groupby 3
> 0 4 1 4
< 4.0
> 1 12 1 4
< 8.0
> 2 8 1 4
< 8.0
> 3 54 2 4
< 54.0
> 4 1 2 2
< 1.0
> 5 7 2 2
< 4.0
> 6 0 2 4
< 27.0
> 7 32 2 2
< 13.333333
```