condition mean min max ZT0-3 15.199074 15.199074 15.199074 ZT4-7 15.944749999999999 15.944749999999999 15.944749999999999 ZT8-11 15.318627499999998 15.318627499999998 15.318627499999998 ZT12-15 16.5922165 16.5922165 16.5922165 ZT16-19 16.255823999999997 16.255823999999997 16.255823999999997 ZT20-23 16.048376 16.048376 16.048376