# Differences Research on Human Overall Comfort Under Low Pressure
## 2 Method
### Experimental Research
#### 2.2.2 Experimental Design  
The subjects were all healthy college students, totaling 60 subjects, primarily recruited from Shandong Province. The detailed information of the subjects is presented in Table 2.  
Figure 1: Plateau simulation cabin. Figure 2: The structural dimensions of the simulation cabin and lamp layout. In terms of their physiological characteristics, since the study population consisted predominantly of young adults, the sample exhibited a certain degree of homogeneity. In the future, participants from different age ranges and various occupations will also be included to enhance the generalizability of the model findings. All experimental procedures were reviewed and approved by the Institutional Review Board of Qingdao University of Technology. A priori sample size calculation and a statistical power analysis were performed. Under the premise of considering a large effect size, it was concluded that the minimum required sample size was 24 subjects, which was smaller than the 60 subjects in this experiment. Therefore, the reliability of the experiment could be ensured. At the same time, based on the actual number of 60 subjects, the statistical power was calculated to be 1 (100%). The current experimental design could reliably detect the significant impact of a single environmental factor on the comfort score. The calculation parameters are shown in Table 3.  
Before entering the cabin, the subjects received simple training, including the experimental content introduction. They were randomly divided into groups of 2 or 4 people. The subjects were required to sit still for 15 min before the experimental survey. During this sitting period, they could engage in light conversation and read books and newspapers but were not allowed to discuss the comfort evaluation. The instruments required for the experiment are shown in Figure 3. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Sex** & **Maximum** & **Minimum** & **Average** & **Standard** \\  & & & & & **Deviation** \\ \hline \multirow{2}{*}{Age} & Male & 26 & 23 & 24 & 1.08 \\  & Female & 26 & 19 & 24 & 1.39 \\ \hline \multirow{2}{*}{Height/cm} & Male & 181 & 170 & 174.6 & 3.34 \\  & Female & 170 & 150 & 162.5 & 6.85 \\ \hline \multirow{2}{*}{Weight/kg} & Male & 100 & 54 & 71.1 & 13.65 \\  & Female & 65 & 46 & 52.8 & 5.72 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Subjects’ essential information. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{2}{c}{**Sample Size Calculation**} & \multicolumn{2}{c}{**Statistical Power Analysis**} \\ \hline
**Test Family:** & **F Tests** & **Test Family:** & **F Tests** \\ \hline \multirow{2}{*}{Statistical test:} & Linear multiple & \multirow{2}{*}{Statistical test:} & Linear multiple \\  & regression & & & regression \\ \hline \multirow{2}{*}{Effect Size \(\ell\)2} & \multirow{2}{*}{0.35} & \multirow{2}{*}{Effect Size \(\ell\)2} & \multirow{2}{*}{0.35} \\  & & & & \\ \hline \multirow{2}{*}{An error probability} & \multirow{2}{*}{0.05} & An error & \multirow{2}{*}{0.05} \\  & & & probability & \\ \hline \multirow{2}{*}{Number of predictors} & \multirow{2}{*}{1} & Number of predictors & \multirow{2}{*}{1} \\ \hline Power (\(1-\beta\)) & 0.8 & N\({}^{\prime}\) & 60 \\ \hline \multirow{2}{*}{N} & **24** & **Power (\(1-\beta\))** & **1 (100\%)** \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The sample size calculation and statistical power analysis. (1) Thermal comfort experiment  
The thermal comfort experiment was divided into winter and summer conditions. To reduce the influence of air velocity, the subjects were required to remain in a windless state during the experiment. The human activity intensity was defined as sitting still. The clothing thermal resistance was relatively fixed: 1.0 clo in winter and 0.5 clo in summer. The main parameters controlled in the thermal comfort experiment included the following: air temperature, wall surface temperature, air velocity, and air pressure. The relative humidity was only measured but not controlled.