condition mean min max ZT0-3 8.782575 8.782575 8.782575 ZT4-7 9.6273975 9.6273975 9.6273975 ZT8-11 9.9585115 9.9585115 9.9585115 ZT12-15 8.909260499999998 8.909260499999998 8.909260499999998 ZT16-19 9.207723999999999 9.207723999999999 9.207723999999999 ZT20-23 8.9230805 8.9230805 8.9230805