wip(thesis): refine preliminaries

src/thesis/preliminaries.tex

@@ -10,7 +10,7 @@ regarding those definitions.
 \section{Terms related to measurement uncertainty}\label{sec:terms-related-to
 -measurement-uncertainty}
 
-\begin{definition}[uncertainty]
+\begin{definition}[Uncertainty]
   \label{def:uncertainty}
   (or \enquote*{measurement uncertainty} or \enquote*{uncertainty of measurement})
   (non-negative) parameter, associated with the result of a measurement, that
@@ -18,7 +18,6 @@ regarding those definitions.
   the measurand
 \end{definition}
 
-
 \begin{definition}[Standard uncertainty]
   \label{def:standard-uncertainty}
   (or \enquote*{standard measurement uncertainty} or \enquote*{standard uncertainty
@@ -35,7 +34,8 @@ regarding those definitions.
   these other quantities weighted according to how the measurement result varies
   with changes in these quantities
   \begin{equation}
-    \uc^2(y) = \sum_{i=1}^{N} \left( \frac{\partial f}{\partial x_i} \right)^2 u^2(x_i)
+    \uc(y) = \sqrt{\sum_{i=1}^{N} \left( \frac{\partial f}{\partial x_i} \right)^2 u^2
+      (x_i)}
     \label{eq:combined-standard-uncertainty}
   \end{equation}
 \end{definition}