condition mean min max ZT0-3 10.125926 10.125926 10.125926 ZT4-7 8.690491 8.690491 8.690491 ZT8-11 10.7952975 10.7952975 10.7952975 ZT12-15 9.6066175 9.6066175 9.6066175 ZT16-19 12.609307 12.609307 12.609307 ZT20-23 16.867057 16.867057 16.867057