condition mean min max ZT0-3 21.059475 19.65035 22.468600000000002 ZT4-7 23.8724 23.8724 23.8724 ZT8-11 36.472049999999996 36.472049999999996 36.472049999999996 ZT12-15 0 0 0 ZT16-19 24.0097 24.0097 24.0097 ZT20-23 28.2213 28.2213 28.2213