condition mean min max ZT0-3 6.490325 5.754435 7.226215 ZT4-7 6.45695 6.45695 6.45695 ZT8-11 8.651205000000001 8.651205000000001 8.651205000000001 ZT12-15 0 0 0 ZT16-19 11.446200000000001 11.446200000000001 11.446200000000001 ZT20-23 11.29735 11.29735 11.29735