condition mean min max ZT0-3 4.7211083333333335 2.120165 6.474785000000001 ZT4-7 1.8665500000000002 1.8665500000000002 1.8665500000000002 ZT8-11 2.953315 2.953315 2.953315 ZT12-15 7.656017500000001 5.482575 9.829460000000001 ZT16-19 6.12593 6.12593 6.12593 ZT20-23 6.80286 6.80286 6.80286