condition mean min max ZT0-3 0.315857 0.315857 0.315857 ZT4-7 0.311521 0.311521 0.311521 ZT8-11 0.280267 0.280267 0.280267 ZT12-15 0.335527 0.335527 0.335527 ZT16-19 0.9081359999999999 0.9081359999999999 0.9081359999999999 ZT20-23 0.8616016666666667 0.8616016666666667 0.8616016666666667