condition mean min max ZT0-3 2.8581433333333335 1.676975 4.01513 ZT4-7 2.423335 2.423335 2.423335 ZT8-11 8.262955 8.262955 8.262955 ZT12-15 17.18162 13.655339999999999 20.7079 ZT16-19 12.05055 12.05055 12.05055 ZT20-23 9.026065 9.026065 9.026065