condition mean min max ZT0-3 10.087325 10.087325 10.087325 ZT4-7 8.11199 8.11199 8.11199 ZT8-11 5.46281 5.46281 5.46281 ZT12-15 6.14143 6.14143 6.14143 ZT16-19 8.24291 8.24291 8.24291 ZT20-23 8.795304999999999 8.795304999999999 8.795304999999999