condition mean min max ZT0-3 9.1741925 8.800460000000001 9.547925 ZT4-7 8.666865 8.666865 8.666865 ZT8-11 8.606020000000001 8.606020000000001 8.606020000000001 ZT12-15 0 0 0 ZT16-19 8.5449 8.5449 8.5449 ZT20-23 10.025535000000001 10.025535000000001 10.025535000000001