condition mean min max ZT0-3 7.986423 7.986423 7.986423 ZT4-7 9.0559205 9.0559205 9.0559205 ZT8-11 10.4045215 10.4045215 10.4045215 ZT12-15 8.627084 8.627084 8.627084 ZT16-19 9.0687185 9.0687185 9.0687185 ZT20-23 8.7507195 8.7507195 8.7507195