condition mean min max ZT0-3 21.33205 21.029649999999997 21.721049999999998 ZT4-7 18.26285 18.26285 18.26285 ZT8-11 21.6348 21.6348 21.6348 ZT12-15 32.853325 31.9005 33.80615 ZT16-19 30.434849999999997 30.434849999999997 30.434849999999997 ZT20-23 28.6685 28.6685 28.6685