condition mean min max ZT0-3 545.443605 545.443605 545.443605 ZT4-7 430.22645 430.22645 430.22645 ZT8-11 387.039329 387.039329 387.039329 ZT12-15 505.807582 505.807582 505.807582 ZT16-19 547.4788195 547.4788195 547.4788195 ZT20-23 555.6280785 555.6280785 555.6280785