condition mean min max ZT0-3 496.809231 496.809231 496.809231 ZT4-7 449.1177705 449.1177705 449.1177705 ZT8-11 370.05969400000004 370.05969400000004 370.05969400000004 ZT12-15 391.89781000000005 391.89781000000005 391.89781000000005 ZT16-19 377.9268415 377.9268415 377.9268415 ZT20-23 427.24902 427.24902 427.24902