condition mean min max ZT0-3 8.603082 8.603082 8.603082 ZT4-7 11.0837795 11.0837795 11.0837795 ZT8-11 8.772224 8.772224 8.772224 ZT12-15 8.547449499999999 8.547449499999999 8.547449499999999 ZT16-19 8.606462 8.606462 8.606462 ZT20-23 8.665624000000001 8.665624000000001 8.665624000000001