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Untitled - Journal of Lighting Engineering

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Although the areas within the<br />

neighbourhoods were rather similar,<br />

different neighbourhood and lighting<br />

components may yield different<br />

connections between the factors.<br />

Regression analysis examines a group <strong>of</strong><br />

independent variables at the same time and<br />

seeks the independent explanatory effects<br />

(controlling for other variables in the<br />

model) instead <strong>of</strong> mere zero-order<br />

correlations; it was therefore considered<br />

suitable for an exploratory study.<br />

Possible connections between the<br />

lighting attributes and safety/pleasantness<br />

were first explored with linear regression<br />

<strong>Lighting</strong> promoting safety and creating a sense <strong>of</strong> pleasantness<br />

analysis (enter method)/standard multiple<br />

regression; the analysis revealed significant<br />

relations between the lighting attributes and<br />

the dependent variables. Only these<br />

attributes were included in the subsequent<br />

regression analysis (enter). Finally, the<br />

suggested connections were tested using the<br />

Spearman correlation as well.<br />

As with in some <strong>of</strong> the statements, the<br />

scale ranged from negative to positive and<br />

again back to negative (e.g. ‘lighting on the<br />

pathway is too strong – totally inadequate’):<br />

Nonlinear regression was also checked, but<br />

no significant nonlinear connections were<br />

detected.<br />

Table 3 Mean values (M) (on 0-6 scale) and standard deviations (SD) for all rating items in the five test areas<br />

(A-E).<br />

4. Results<br />

Descriptive statistics are presented in Table 3.<br />

Brightness perceptions corresponded well<br />

with the luminance measurements whereas<br />

there were considerable differences<br />

between the TI values and perceived glare<br />

measurements. However, as stated before,<br />

TI values describe disability glare in road<br />

lighting conditions, whereas perceived glare<br />

describes the subjective feeling <strong>of</strong><br />

discomfort.<br />

Data on the significant (p≤0.05)<br />

connections and coefficients are presented<br />

in Table 4 (perceived safety) and Table 5<br />

(pleasant lighting). The tables present the<br />

significant coefficients indicated by the<br />

linear regression analysis (enter method).<br />

After conducting regression analysis, we<br />

used the Spearman correlation test. Data on<br />

the significant correlations (Spearman<br />

correlation, p≤0.05) between the variables<br />

are provided in Table 6 (perceived safety)<br />

and Table 7 (pleasant lighting).<br />

Ingineria Iluminatului 2012; 14, 2: 33-46 39

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