condition mean min max ZT0-3 370.847673 370.847673 370.847673 ZT4-7 315.91972599999997 315.91972599999997 315.91972599999997 ZT8-11 268.99689950000004 268.99689950000004 268.99689950000004 ZT12-15 319.22123750000003 319.22123750000003 319.22123750000003 ZT16-19 294.27021249999996 294.27021249999996 294.27021249999996 ZT20-23 280.90475 280.90475 280.90475