condition mean min max ZT0-3 391.151597 391.151597 391.151597 ZT4-7 334.27285900000004 334.27285900000004 334.27285900000004 ZT8-11 280.4028865 280.4028865 280.4028865 ZT12-15 323.503248 323.503248 323.503248 ZT16-19 410.50703 410.50703 410.50703 ZT20-23 489.4023495 489.4023495 489.4023495