condition mean min max ZT0-3 826.724364 826.724364 826.724364 ZT4-7 310.53326749999997 310.53326749999997 310.53326749999997 ZT8-11 263.6431785 263.6431785 263.6431785 ZT12-15 321.561333 321.561333 321.561333 ZT16-19 437.6448515 437.6448515 437.6448515 ZT20-23 556.034318 556.034318 556.034318