# The Influence of Classroom Illumination Environment on the Efficiency of Foreign Language Learning
## 4 Determination of Salivary Amylase Activity
### Results  
Table 4 shows every group's salivary amylase activity in different illumination environments, whose value was measured in KU/L, where KU/L = 1000 U/1000 ML = 1 U/ML, representing how active the amylase was in saliva. The stress evaluation depended on the change rate of salivary amylase activity.  
\[N\ =\ \frac{A-B}{A}\times 100\% \tag{1}\]  
where \(N\) is the change rate (%) of salivary amylase activity, A is the value measured before entry into the designed illuminating condition, and B is the value measured after entry into the designed illuminating condition. After entry into the designed illuminating condition, the change rate is positive when the salivary amylase activity is lowering, indicating relieving stress (sympathetic nerves are static); on the contrary, in the designed illuminating condition, the change rate is negative when the salivary amylase activity is rising, indicating increasing stress (sympathetic nerves are excited).  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & & & & & & & & & \\ \hline \hline \multirow{2}{*}{**Mean**} & \multirow{2}{*}{**Std. Deviation**} & \multirow{2}{*}{**Std. Error Mean**} & \multicolumn{3}{c}{**95\% Confidence Interval of**} & \multirow{2}{*}{**t**} & \multirow{2}{*}{**df**} & \multirow{2}{*}{**Sig. (2-Tailed)**} \\  & & & & & & & & & \\ \cline{5-8}  & & & & & & & & & \\ \hline \hline Pair 1 & \multirow{2}{*}{\(-\)6.400} & \multirow{2}{*}{1.949} & \multirow{2}{*}{0.871} & \multirow{2}{*}{-8.820} & \multirow{2}{*}{-3.979} & \multirow{2}{*}{-7.341} & \multirow{2}{*}{4} & \multirow{2}{*}{0.002} \\ (Case 1-Case 2) & & & & & & & & & \\ \hline Pair 2 & \multirow{2}{*}{7.600} & \multirow{2}{*}{3.209} & \multirow{2}{*}{1.435} & \multirow{2}{*}{3.615} & \multirow{2}{*}{11.584} & \multirow{2}{*}{5.295} & \multirow{2}{*}{4} & \multirow{2}{*}{0.006} \\ (Case 1-Case 3) & & & & & & & & & \\ \hline Pair 3 & \multirow{2}{*}{4.200} & \multirow{2}{*}{3.563} & \multirow{2}{*}{1.593} & \multirow{2}{*}{-0.224} & \multirow{2}{*}{8.624} & \multirow{2}{*}{2.635} & \multirow{2}{*}{4} & \multirow{2}{*}{0.058} \\ (Case 2-Case 3) & & & & & & & & & \\ \hline Pair 5 & \multirow{2}{*}{10.600} & \multirow{2}{*}{1.949} & \multirow{2}{*}{0.871} & \multirow{2}{*}{8.179} & \multirow{2}{*}{13.020} & \multirow{2}{*}{12.159} & \multirow{2}{*}{4} & \multirow{2}{*}{0.000} \\ (Case 2-Case 4) & & & & & & & & & \\ \hline Pair 6 & \multirow{2}{*}{\(-\)3.400} & \multirow{2}{*}{0.894} & \multirow{2}{*}{0.400} & \multirow{2}{*}{-4.510} & \multirow{2}{*}{-2.289} & \multirow{2}{*}{-8.500} & \multirow{2}{*}{4} & \multirow{2}{*}{0.001} \\ (Case 3-Case 4 & & & & & & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 3: T-test results.  
Due to individual difference of participants, the maximum difference of salivary amylase activity values between different participants was nearly 80 KU/L, so every group's measured values were averaged (Table 4). According to these statistics, in different illumination environments the salivary amylase activity value was different, in a sequence from high to low: Case 3 (5000 K, 325 lx), Case 1 (5000 K, 650 lx), Case 4 (4000 K, 325 lx), and Case 2 (4000 K, 650 lx), i.e., higher values appeared in higher stress while lower values appeared in lower stress (Figure 5). The change rate of salivary amylase activity was positive in Case 2 (4000 K, 650 lx) and Case 4 (4000 K, 325 lx), respectively, and 0.09% in Case 2 and 0.13% in Case 4, which meant that in these two illumination environments, Japanese language learning stress was reduced; the change rate was negative in Case 3 (5000 K, 325 lx) and Case 1 (5000 K, 650 lx), respectively, and \(-\)0.24% in Case 3 and \(-\)0.19% in Case 1, which meant that in these two illumination environments, Japanese language learning stress was increased.