Выражение встречается в следующем контексте:The expanded uncertainty of the measurements at 95% confidence...

Заранее спасибо

Expanded uncertainty
Although the combined standard uncertainty uc is used to express the uncertainty of many measurement results, for some commercial, industrial, and regulatory applications (e.g., when health and safety are concerned), what is often required is a measure of uncertainty that defines an interval about the measurement result y within which the value of the measurand Y can be confidently asserted to lie. The measure of uncertainty intended to meet this requirement is termed expanded uncertainty, suggested symbol U, and is obtained by multiplying uc(y) by a coverage factor, suggested symbol k. Thus U = kuc(y) and it is confidently believed that Y is greater than or equal to y - U, and is less than or equal to y + U, which is commonly written as Y = y ± U.

Расширенная погрешность
http://www.nucleide.org/DDEP_WG/explanation_russian.pdf
http://www.propivo.ru/sens/01/40.html

только что столкнулась сама с этим. в русс доке это именно так