condition mean min max ZT0-3 8.206109 8.206109 8.206109 ZT4-7 8.795402 8.795402 8.795402 ZT8-11 7.7001085 7.7001085 7.7001085 ZT12-15 8.000871 8.000871 8.000871 ZT16-19 8.206109 8.206109 8.206109 ZT20-23 8.408660000000001 8.408660000000001 8.408660000000001