``` In [44]: import pandas.rpy.common as com In [45]: cw = com.load_data('ChickWeight') Chick weight 1 0.0 10.5 41.4 2.0 10.5 47.25 4.0 10.11 56.47 6.0 10.11 66.79 8.0 10.11 79.68 10.0 10.11 93.05 12.0 10.11 108.5 14.0 9.778 123.4 16.0 9.471 144.6 18.0 9.471 158.9 20.0 9.471 170.4 21.0 9.562 177.8 2 0.0 25.5 40.7 2.0 25.5 49.4 4.0 25.5 59.8 6.0 25.5 75.4 8.0 25.5 91.7 In [47]: cw.groupby(['Diet', 'Time']).mean().ix[1] Out[47]: Chick 10.5 weight 47.25 ```