condition mean min max ZT0-3 11.668514 11.668514 11.668514 ZT4-7 9.2769255 9.2769255 9.2769255 ZT8-11 9.383564 9.383564 9.383564 ZT12-15 8.8733475 8.8733475 8.8733475 ZT16-19 9.550580499999999 9.550580499999999 9.550580499999999 ZT20-23 8.9348265 8.9348265 8.9348265