*3.1. Descriptive Anaylses. Mean and Standard Deviations*

Students' perception of the indoor environment of their classes ranges from values close to 4 and above 6 (see Table 2). Appreciation for the color of the walls is the worst valued (m = 3.84), followed by the chair comfort, the ventilation and the amount of natural light. While the best rated is the acoustic comfort, followed by classroom size, the learning space attachment and the connection with nature.


Table 3 shows the descriptive analysis results in relation to the average grade of Mathematics (mM = 7.48) and Arts (mA = 8.24), since it has a different scale: 0–10.


**Table 3.** Descriptive values of mathematics and art education average grade.

Figure 2 corresponds to the analysis of the distribution of the learning space and academic variables through a boxplot diagram. In almost all cases of the iPEP variables, the lower limit is 1, while the upper limit is 7. However, the quartiles in the case of the acoustic variable are grouped in a much lower range than the rest of the variables, practically 100 per cent of the sample is located between values 5 and 7. The rest of the variables distribute the data in a range of values 1 and 7.

**Figure 2.** iPEP boxplot.

The variables Natural light, Room size, Chair comfort and Space appropriation are grouped into smaller ranges of values. While the color variable occupies a greater range between the values 2 and 6.

Subsequently, the mean variable values of the student perception of each classroom were made in order to obtain a global measurement. Figure 3 shows the dispersion of the iPEP variable mean values for each of the 27 classrooms, indicating the variability that exists in each of them.

**Figure 3.** iPEP mean values by classroom.

Classrooms 10 and 23 have a higher concentration in the grouping of iPEP values, with values between 5–6.5; and 4.6–5.7, respectively. On the contrary, classrooms 6, 7, and 19 indicate values between 2.2 and 6.1; 2.7 and 6.6; and 2.5 and 6.7. Moreover, this figure allows us to analyze whether the sets of means are superior or inferior to the rest of classrooms. In this case, classrooms 18, 20, and 21 indicate a concentration in lower values, followed by 6 and 22. On the other hand, classrooms 5, 11, and 12 are grouped in the highest values, followed by 13 and 3.
