condition mean min max ZT0-3 4.610315 2.66875 5.61963 ZT4-7 3.675235 3.675235 3.675235 ZT8-11 4.333035000000001 4.333035000000001 4.333035000000001 ZT12-15 6.3407475 6.081175 6.60032 ZT16-19 5.42287 5.42287 5.42287 ZT20-23 6.78423 6.78423 6.78423