condition mean min max ZT0-3 3.963655 3.963655 3.963655 ZT4-7 3.641305 3.641305 3.641305 ZT8-11 3.35577 3.35577 3.35577 ZT12-15 1.914705 1.914705 1.914705 ZT16-19 2.5324600000000004 2.5324600000000004 2.5324600000000004 ZT20-23 0.948385 0.948385 0.948385