condition mean min max ZT0-3 10.045275 8.26661 11.82394 ZT4-7 7.28631 7.28631 7.28631 ZT8-11 9.296804999999999 9.296804999999999 9.296804999999999 ZT12-15 0 0 0 ZT16-19 10.725670000000001 10.725670000000001 10.725670000000001 ZT20-23 13.164470000000001 13.164470000000001 13.164470000000001