condition mean min max ZT0-3 6.668806666666667 6.38158 7.068465 ZT4-7 6.502935000000001 6.502935000000001 6.502935000000001 ZT8-11 13.424299999999999 13.424299999999999 13.424299999999999 ZT12-15 14.45785 12.487300000000001 16.4284 ZT16-19 12.78225 12.78225 12.78225 ZT20-23 8.86547 8.86547 8.86547