Change example to compute aggregation on each group #17845

Job	Run time
devcontainer / amd64, 12.5, conda	1h 56m 48s
devcontainer / amd64, 12.5, pip	1h 49m 29s
checks / other-checks	1m 0s
changed-files / Check changed files	27s
checks / check-style	2m 49s
wheel-build-libcudf	0s
static-configure	0s
conda-cpp-build	0s
wheel-build-pylibcudf	0s
conda-cpp-checks	0s
conda-python-build	0s
conda-cpp-tests	0s
conda-java-tests	0s
wheel-build-cudf	0s
wheel-build-cudf-polars	0s
conda-python-cudf-tests	0s
conda-notebook-tests	0s
conda-python-other-tests	0s
docs-build	0s
wheel-build-dask-cudf	0s
wheel-tests-cudf	0s
unit-tests-cudf-pandas	0s
cudf-polars-polars-tests	0s
pandas-tests	0s
wheel-tests-cudf-polars	0s
wheel-tests-dask-cudf	0s
pandas-tests-diff	0s
pr-builder / run	1s
	3h 50m 34s

Provide feedback