Table 3.

t-test results for heading r-value against season.

Period	Group 1	Group 2	t	df	p
Daytime	Spring	Summer	−3.237	319	0.0013
	Spring	Autumn	−9.816	381	<0.0001
	Summer	Autumn	−5.737	337	<0.0001
Sunset	Spring	Summer	−5.292	269	<0.0001
	Spring	Autumn	−10.323	519	<0.0001
	Summer	Autumn	−2.680	291	0.0078
Night	Spring	Summer	4.666	191	<0.0001
	Spring	Autumn	−0.804	212	0.4223
	Summer	Autumn	−5.982	208	<0.0001
All period	Daytime	Sunset	3.292	1154	0.0010
	Daytime	Night	−0.612	912	0.5405
	Sunset	Night	−3.862	858	0.0001