condition mean min max ZT0-3 4.348515 4.348515 4.348515 ZT4-7 3.97164 3.97164 3.97164 ZT8-11 3.9711 3.9711 3.9711 ZT12-15 4.1080950000000005 4.1080950000000005 4.1080950000000005 ZT16-19 5.847655 5.847655 5.847655 ZT20-23 4.433635000000001 4.433635000000001 4.433635000000001