condition mean min max ZT0-3 7.62285 6.21431 9.03139 ZT4-7 6.9072499999999994 6.9072499999999994 6.9072499999999994 ZT8-11 6.45596 6.45596 6.45596 ZT12-15 8.438277916666667 7.6961825 9.180373333333334 ZT16-19 9.50104 8.53755 10.46453 ZT20-23 0 0 0