condition mean min max ZT0-3 280.146406 280.146406 280.146406 ZT4-7 469.69222249999996 469.69222249999996 469.69222249999996 ZT8-11 428.9835495 428.9835495 428.9835495 ZT12-15 321.045201 321.045201 321.045201 ZT16-19 189.2515465 189.2515465 189.2515465 ZT20-23 229.208259 229.208259 229.208259