condition mean min max ZT0-3 8.107985 7.6293500000000005 8.58662 ZT4-7 8.55546 8.55546 8.55546 ZT8-11 18.0817 18.0817 18.0817 ZT12-15 0 0 0 ZT16-19 17.18055 17.18055 17.18055 ZT20-23 10.001190000000001 10.001190000000001 10.001190000000001