condition mean min max ZT0-3 16.942186 16.942186 16.942186 ZT4-7 18.0147725 18.0147725 18.0147725 ZT8-11 18.6328935 18.6328935 18.6328935 ZT12-15 17.066139 17.066139 17.066139 ZT16-19 17.574837 17.574837 17.574837 ZT20-23 19.825263 19.825263 19.825263