Figure 2 : Plot of populations of Blue and Red Globular Clusters for 18 high quality 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 = 18 c1 c2 Spearman rho probability of correlation c1 c2 Spearman rho probability of correlation

High Quality sample
Blue/Red GC
vs.
Velocity Dispersion 0.320 ± 0.079
(4.1 sigma) 0.403 ± 0.186 0.734 99.75% 0.166 ± 0.078
(2.1 sigma) 0.547 ± 0.186 0.495 95.88%

Data set	Red				Blue
N = 18	c1	c2	Spearman rho	probability of correlation	c1	c2	Spearman rho	probability of correlation
High Quality sample Blue/Red GC vs. Velocity Dispersion	0.320 ± 0.079 (4.1 sigma)	0.403 ± 0.186	0.734	99.75%	0.166 ± 0.078 (2.1 sigma)	0.547 ± 0.186	0.495	95.88%