condition mean min max ZT0-3 6.8603000000000005 6.8603000000000005 6.8603000000000005 ZT4-7 5.737665 5.737665 5.737665 ZT8-11 4.013565 4.013565 4.013565 ZT12-15 5.389105 5.389105 5.389105 ZT16-19 7.43357 7.43357 7.43357 ZT20-23 5.665789999999999 5.665789999999999 5.665789999999999