Figure 4 : Plot of populations of Blue and Red Globular Clusters for 40 galaxies

Statistical tests

Least squares weighted best fit y = c1 * x + c2

Spearman Rank test was used to test probability of correlation

Data set Red Blue

N = 40 c1 c2 Spearman rho probability of correlation c1 c2 Spearman rho probability of correlation

Full sample
Blue/Red GC
vs.
Mv -0.025 ± 0.009
(2.8 sigma) 0.626 ± 0.194 -0.435 99.34% -0.010 ± 0.009
(1.1 sigma) 0.736 ± 0.197 -0.237 86.15%

Data set	Red				Blue
N = 40	c1	c2	Spearman rho	probability of correlation	c1	c2	Spearman rho	probability of correlation
Full sample Blue/Red GC vs. Mv	-0.025 ± 0.009 (2.8 sigma)	0.626 ± 0.194	-0.435	99.34%	-0.010 ± 0.009 (1.1 sigma)	0.736 ± 0.197	-0.237	86.15%