condition mean min max ZT0-3 14.515582 14.515582 14.515582 ZT4-7 12.516862 12.516862 12.516862 ZT8-11 13.024716000000002 13.024716000000002 13.024716000000002 ZT12-15 11.5608025 11.5608025 11.5608025 ZT16-19 13.0792915 13.0792915 13.0792915 ZT20-23 11.9007315 11.9007315 11.9007315