condition mean min max ZT0-3 23.914524 23.914524 23.914524 ZT4-7 22.781321 22.781321 22.781321 ZT8-11 20.0278925 20.0278925 20.0278925 ZT12-15 18.5508345 18.5508345 18.5508345 ZT16-19 25.2963565 25.2963565 25.2963565 ZT20-23 22.049774499999998 22.049774499999998 22.049774499999998