condition mean min max ZT0-3 2.5272778645000002 2.024900088 3.029655641 ZT4-7 1.96292506825 1.8243951264999998 2.10145501 ZT8-11 2.77147808875 2.271035334 3.2719208435 ZT12-15 3.33853079 3.0144056975 3.6626558825 ZT16-19 4.073615612999999 3.499739121 4.6474921049999995 ZT20-23 6.615298318750001 5.934543120500001 7.296053517000001