condition mean min max ZT0-3 19.148407 19.148407 19.148407 ZT4-7 17.486294 17.486294 17.486294 ZT8-11 16.028444 16.028444 16.028444 ZT12-15 21.095954 21.095954 21.095954 ZT16-19 16.145719 16.145719 16.145719 ZT20-23 16.5214715 16.5214715 16.5214715