condition mean min max ZT0-3 2.271925 2.083455 2.460395 ZT4-7 4.642115 4.642115 4.642115 ZT8-11 5.21472 5.21472 5.21472 ZT12-15 0 0 0 ZT16-19 3.208275 3.208275 3.208275 ZT20-23 3.05415 3.05415 3.05415