condition mean min max ZT0-3 489.465634 489.465634 489.465634 ZT4-7 504.4627085 504.4627085 504.4627085 ZT8-11 454.5939265 454.5939265 454.5939265 ZT12-15 447.32200950000004 447.32200950000004 447.32200950000004 ZT16-19 510.404953 510.404953 510.404953 ZT20-23 408.06657099999995 408.06657099999995 408.06657099999995