t.from t.to intervention participants events   py 
   0    6        1            2263      14   1172.1
   0    6        0            2319      19   1206.7
   6   12        1            2235       5   1190.7
   6   12        0            2229      14   1176.3
  12   24        1             964       3    989.7 
  12   24        0             980      12   1008.7