condition mean min max ZT0-3 234.770391 234.770391 234.770391 ZT4-7 278.709204 278.709204 278.709204 ZT8-11 254.072191 254.072191 254.072191 ZT12-15 266.306304 266.306304 266.306304 ZT16-19 258.3876275 258.3876275 258.3876275 ZT20-23 266.7320565 266.7320565 266.7320565