condition mean min max ZT0-3 18.741966666666666 15.180299999999999 20.8763 ZT4-7 14.65745 14.65745 14.65745 ZT8-11 15.47455 15.47455 15.47455 ZT12-15 19.683925000000002 17.42685 21.941000000000003 ZT16-19 18.0428 18.0428 18.0428 ZT20-23 25.9606 25.9606 25.9606