condition mean min max ZT0-3 3.1380049999999997 3.1380049999999997 3.1380049999999997 ZT4-7 2.389455 2.389455 2.389455 ZT8-11 2.773305 2.773305 2.773305 ZT12-15 4.240785000000001 4.240785000000001 4.240785000000001 ZT16-19 4.7755 4.7755 4.7755 ZT20-23 3.12783 3.12783 3.12783