condition mean min max ZT0-3 8.016595 8.016595 8.016595 ZT4-7 18.47214 18.47214 18.47214 ZT8-11 13.895555 13.895555 13.895555 ZT12-15 10.9852545 10.9852545 10.9852545 ZT16-19 7.5738225 7.5738225 7.5738225 ZT20-23 6.992998 6.992998 6.992998