condition mean min max ZT0-3 39.76260639 39.44824912 40.07696366 ZT4-7 16.895746459 13.435518203 20.355974715000002 ZT8-11 9.40659974 7.91380981 10.899389670000001 ZT12-15 23.61311598575 19.0184674415 28.20776453 ZT16-19 38.744992815 37.507527865 39.982457765 ZT20-23 32.6300571775 31.800478769999998 33.459635585