condition mean min max ZT0-3 52.1893854 42.77770218 61.60106862 ZT4-7 31.429418975 29.57568012 33.28315783 ZT8-11 29.79723587 29.336079523333332 30.258392216666667 ZT12-15 33.43337065 25.27285272 41.59388858 ZT16-19 63.11287559833333 59.953205546666666 66.27254565 ZT20-23 71.545159365 70.50824733666667 72.58207139333334