condition mean min max ZT0-3 20.73465 20.73465 20.73465 ZT4-7 14.8958 14.8958 14.8958 ZT8-11 13.39845 13.39845 13.39845 ZT12-15 17.246499999999997 17.246499999999997 17.246499999999997 ZT16-19 21.77265 21.77265 21.77265 ZT20-23 23.834699999999998 23.834699999999998 23.834699999999998