condition mean min max ZT0-3 18.436826 18.436826 18.436826 ZT4-7 13.130541000000001 13.130541000000001 13.130541000000001 ZT8-11 11.7359425 11.7359425 11.7359425 ZT12-15 15.2584385 15.2584385 15.2584385 ZT16-19 11.5937145 11.5937145 11.5937145 ZT20-23 13.91649 13.91649 13.91649