condition mean min max ZT0-3 8.78439 8.78439 8.78439 ZT4-7 6.222745 6.222745 6.222745 ZT8-11 6.3388100000000005 6.3388100000000005 6.3388100000000005 ZT12-15 10.035530000000001 10.035530000000001 10.035530000000001 ZT16-19 11.642299999999999 11.642299999999999 11.642299999999999 ZT20-23 9.78378 9.78378 9.78378