condition mean min max ZT0-3 8.509635 8.509635 8.509635 ZT4-7 11.26835 11.26835 11.26835 ZT8-11 6.07457 6.07457 6.07457 ZT12-15 4.45395 4.45395 4.45395 ZT16-19 4.489385 4.489385 4.489385 ZT20-23 5.6513349999999996 5.6513349999999996 5.6513349999999996