condition mean min max ZT0-3 6.825065 6.825065 6.825065 ZT4-7 5.27921 5.27921 5.27921 ZT8-11 4.177665 4.177665 4.177665 ZT12-15 6.45956 6.45956 6.45956 ZT16-19 6.218975 6.218975 6.218975 ZT20-23 8.296425 8.296425 8.296425