condition mean min max ZT0-3 4.669228333333333 3.63368 5.263335 ZT4-7 3.27083 3.27083 3.27083 ZT8-11 2.7291800000000004 2.7291800000000004 2.7291800000000004 ZT12-15 4.87242 4.8421 4.90274 ZT16-19 4.221395 4.221395 4.221395 ZT20-23 5.84409 5.84409 5.84409