condition mean min max ZT0-3 4.120385 4.120385 4.120385 ZT4-7 3.75877 3.75877 3.75877 ZT8-11 3.167465 3.167465 3.167465 ZT12-15 3.66663 3.66663 3.66663 ZT16-19 3.6757150000000003 3.6757150000000003 3.6757150000000003 ZT20-23 3.6241649999999996 3.6241649999999996 3.6241649999999996