condition mean min max ZT0-3 9.538025 9.538025 9.538025 ZT4-7 12.1995465 12.1995465 12.1995465 ZT8-11 9.043548000000001 9.043548000000001 9.043548000000001 ZT12-15 9.426572499999999 9.426572499999999 9.426572499999999 ZT16-19 9.3480305 9.3480305 9.3480305 ZT20-23 8.758236 8.758236 8.758236