condition mean min max ZT0-3 1538.111243 1345.35299 1730.869496 ZT4-7 1149.29854135 859.8435211999999 1438.7535615000002 ZT8-11 266.21709359 131.95503351 400.47915367 ZT12-15 198.826617755 125.397673085 272.255562425 ZT16-19 538.8731802249999 504.69898555 573.0473749 ZT20-23 627.5035942 626.6065902 628.4005982