condition mean min max ZT0-3 20.79735 20.5182 21.0765 ZT4-7 8.722665 8.722665 8.722665 ZT8-11 8.89498 8.89498 8.89498 ZT12-15 0 0 0 ZT16-19 18.7678 18.7678 18.7678 ZT20-23 19.6186 19.6186 19.6186