condition mean min max ZT0-3 8.459285 7.986075 8.932495 ZT4-7 8.813745 8.813745 8.813745 ZT8-11 7.745385000000001 7.745385000000001 7.745385000000001 ZT12-15 0 0 0 ZT16-19 10.47219 10.47219 10.47219 ZT20-23 10.33925 10.33925 10.33925