condition mean min max ZT0-3 5.64997 5.64997 5.64997 ZT4-7 4.647995 4.647995 4.647995 ZT8-11 5.74813 5.74813 5.74813 ZT12-15 6.18408 6.18408 6.18408 ZT16-19 7.334985 7.334985 7.334985 ZT20-23 5.983125 5.983125 5.983125