condition mean min max ZT0-3 1.305965 1.305965 1.305965 ZT4-7 0.819518 0.819518 0.819518 ZT8-11 0.6410545000000001 0.6410545000000001 0.6410545000000001 ZT12-15 0.722439 0.722439 0.722439 ZT16-19 0.429364 0.429364 0.429364 ZT20-23 0.3150153333333333 0.3150153333333333 0.3150153333333333