Please interpret the output below. What type of test was used and why? Are energ
ID: 3366124 • Letter: P
Question
Please interpret the output below. What type of test was used and why? Are energy costs lower for LEED-certified buildings in this output? These data have an effect size of d = .39. How does that add to your interpretation of the results?
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
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
Explanation / Answer
ANSWER:
Here student independent sample 't' test was used.
Reason: Here two independent groups are there and also we are testing mean energy costs between two groups.
IT IS A ONE - TAILED TEST
Here research hypothesis is Are energy costs lower for LEED-certified buildings in this output?
Ho: mean difference = 0 Vs. H1: mean1<mean2
Therefore t-statistic = -1.678 and one tailed p = 0.048
Here p <0.05 hence we reject Null hypothesis.
Conclusion: There was an enough evidence that the energy costs lower for LEED-certified buildings
Here effect size of d = .39, it indicates medium effect i.e. likely to be different in the means.