condition mean min max ZT0-3 8.62907 8.62907 8.62907 ZT4-7 9.484808000000001 9.484808000000001 9.484808000000001 ZT8-11 8.7627555 8.7627555 8.7627555 ZT12-15 8.904114499999999 8.904114499999999 8.904114499999999 ZT16-19 8.931239 8.931239 8.931239 ZT20-23 8.9675315 8.9675315 8.9675315