condition mean min max ZT0-3 5.32491 3.21708 7.503415 ZT4-7 2.2500400000000003 2.2500400000000003 2.2500400000000003 ZT8-11 1.8812024999999999 1.8812024999999999 1.8812024999999999 ZT12-15 2.5045124999999997 2.114475 2.8945499999999997 ZT16-19 3.73991 3.73991 3.73991 ZT20-23 5.46064 5.46064 5.46064