condition mean min max ZT0-3 8.87888889 8.87888889 8.87888889 ZT4-7 7.782222222333334 7.782222222333334 7.782222222333334 ZT8-11 9.131111113333333 9.131111113333333 9.131111113333333 ZT12-15 11.528888890000001 11.528888890000001 11.528888890000001 ZT16-19 19.6 19.6 19.6 ZT20-23 14.280000000000001 14.280000000000001 14.280000000000001