Possible Typo in 09_tabular notebook:
I believe the cell near the end that contains:
xs_filt2 = xs_filt.drop('fiModelDescriptor', axis=1)
valid_xs_time2 = valid_xs_time.drop('fiModelDescriptor', axis=1)
m2 = rf(xs_filt2, y_filt)
m_rmse(m, xs_filt2, y_filt), m_rmse(m2, valid_xs_time2, valid_y)
contains a typo in the last line, because the xs_filt2 is not the same set of x(s) that was used to create m. I believe that line should be:
m_rmse(m, xs_filt, y_filt), m_rmse(m2, valid_xs_time2, valid_y)