condition mean min max ZT0-3 12.618324 12.618324 12.618324 ZT4-7 13.548542000000001 13.548542000000001 13.548542000000001 ZT8-11 15.071705000000001 15.071705000000001 15.071705000000001 ZT12-15 13.691072 13.691072 13.691072 ZT16-19 13.3511815 13.3511815 13.3511815 ZT20-23 14.4345335 14.4345335 14.4345335