condition mean min max ZT0-3 12.888331 12.888331 12.888331 ZT4-7 12.6945965 12.6945965 12.6945965 ZT8-11 12.617296 12.617296 12.617296 ZT12-15 13.303721 13.303721 13.303721 ZT16-19 13.267404500000001 13.267404500000001 13.267404500000001 ZT20-23 12.893805 12.893805 12.893805