Please interpret the output below. What type of test was used and why? Is there a significant difference between these two means?

	Yearly Energy Costs LEED- Certified Buildings (in thousands of $)	Yearly Energy Costs non-LEED- Certified Buildings (in thousands of $)
Mean	18.22	21.46
Variance	1548.27	1318.33
Observations	60	55
Hypothesized Mean Difference	0
df	73
t Stat	-1.678
P(T<=t) one-tail	0.048
t Critical one-tail	1.667
P(T<=t) two-tail	0.096
t Critical two-tail	1.993