condition mean min max ZT0-3 11.074471 11.074471 11.074471 ZT4-7 11.8402265 11.8402265 11.8402265 ZT8-11 11.758264 11.758264 11.758264 ZT12-15 9.626295500000001 9.626295500000001 9.626295500000001 ZT16-19 11.745750000000001 11.745750000000001 11.745750000000001 ZT20-23 10.415085 10.415085 10.415085