condition mean min max ZT0-3 23.524964 23.524964 23.524964 ZT4-7 20.6488355 20.6488355 20.6488355 ZT8-11 23.2654865 23.2654865 23.2654865 ZT12-15 20.929911 20.929911 20.929911 ZT16-19 17.534058 17.534058 17.534058 ZT20-23 18.4188615 18.4188615 18.4188615