但如果不知道有效自由度是否大于10，而直接取扩展不确定度等于两倍的合成标准不确定度是存在疑虑的。

But if we are not sure about whether the effective freedom degree is more than 10, it is doubtful that selecting expanded uncertainty as twice as combined standard uncertainty.

youdao

但如果不知道有效自由度是否大于10，而直接取扩展不确定度等于两倍的合成标准不确定度是存在疑虑的。

But if we are not sure about whether the effective freedom degree is more than 10, it is doubtful that selecting expanded uncertainty as twice as combined standard uncertainty.

youdao