condition mean min max ZT0-3 20.335061 20.335061 20.335061 ZT4-7 18.178904000000003 18.178904000000003 18.178904000000003 ZT8-11 19.2671385 19.2671385 19.2671385 ZT12-15 20.507917 20.507917 20.507917 ZT16-19 22.0248055 22.0248055 22.0248055 ZT20-23 32.293477 32.293477 32.293477