Table 3.

Results of analyzing correlatn coefficients among certain factors of natural light: cloudy days.

Correlation Coefficient	SWR	MWR	LWR	tristimulus_X	tristimulus_Y	tristimulus_Z	color_coordinate_x	color_coordinate_y	illuminance	CCT
SWR (Short $\mathrm{Wavelengh} \mathrm{Ratio})$	1	−0.994	0.922	0.279	0.289	0.433	− 0.991	− 0.992	0.289	0.991
MWR ($\mathrm{Middle} \mathrm{Wavelengh} \mathrm{Ratio})$	−0.994	1	−0.958	−0.305	−0.315	−0.449	0.994	0.979	−0.315	−0.984
LWR ($\mathrm{Long} \mathrm{Wavelengh} \mathrm{Ratio})$	0.922	−0.958	1	0.358	0.368	0.467	−0.946	−0.887	0.368	0.908
tristimulus_X	0.279	−0.305	0.358	1	1	0.981	−0.263	−0.24	1	0.184
tristimulus_Y	0.289	−0.315	0.368	1	1	0.983	−0.273	−0.25	1	0.194
tristimulus_Z	0.433	−0.449	0.467	0.981	0.983	1	−0.411	−0.401	0.983	0.341
color_coordinate_x	−0.991	0.994	−0.946	−0.263	−0.273	−0.411	1	0.987	−0.273	− 0.985
color_coordinate_y	−0.992	0.979	−0.887	−0.24	−0.25	−0.401	0.987	1	−0.25	− 0.985
Illuminance	0.289	−0.315	0.368	1	1	0.983	−0.273	−0.25	1	0.194
CCT (color temperature)	0.991	−0.984	0.908	0.184	0.194	0.341	−0.985	−0.985	0.194	1