condition mean min max ZT0-3 7.0943475 7.05016 7.138535 ZT4-7 6.4984649999999995 6.4984649999999995 6.4984649999999995 ZT8-11 6.88269 6.88269 6.88269 ZT12-15 0 0 0 ZT16-19 8.33863 8.33863 8.33863 ZT20-23 7.572405 7.572405 7.572405