condition mean min max ZT0-3 412.577324 412.577324 412.577324 ZT4-7 339.24210200000005 339.24210200000005 339.24210200000005 ZT8-11 192.0853725 192.0853725 192.0853725 ZT12-15 218.802101 218.802101 218.802101 ZT16-19 284.43528349999997 284.43528349999997 284.43528349999997 ZT20-23 263.4766155 263.4766155 263.4766155