Table 1. Results of the non-parametric Mann Whitney U Test for all pairs of classes.

		p-value
Pair		Reflection	Speed of Sound	Attenuation
skin	fat	<0.0001	<0.0001	<0.0001
skin	glands	<0.0001	0.1597	<0.0001
skin	ducts	<0.0001	<0.0001	<0.0001
glands	fat	<0.0001	<0.0001	0.0058
glands	ducts	0.5379	<0.0001	0.049
fat	ducts	<0.0001	<0.0001	0.2943
skin	CT	<0.0001	<0.0001	0.0005
ducts	CT	<0.0001	<0.0001	<0.0001
glands	CT	<0.0001	<0.0001	<0.0001
fat	CT	<0.0001	<0.0001	0.0007

Note that a p-value of less than 0.05 indicates significance. CT = connective tissue.