using excel>addins>phstat>one sample t test
we have
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t Test for Hypothesis of the Mean |
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Data |
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Null
Hypothesis              Â
m= |
16500 |
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Level of Significance |
0.05 |
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Sample Size |
250 |
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Sample Mean |
14651.548 |
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Sample Standard Deviation |
7980.99357 |
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Intermediate Calculations |
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Standard Error of the Mean |
504.7624 |
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Degrees of Freedom |
249 |
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t Test Statistic |
-3.6620 |
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Lower-Tail Test |
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Calculations Area |
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Lower Critical Value |
-1.6510 |
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For one-tailed tests: |
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p-Value |
0.0002 |
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T.DIST.RT value |
0.000152807 |
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Reject the null hypothesis |
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1-T.DIST.RT value |
0.999847193 |
since p value is less than 0.05 so we have sufficient evidence
to conclude that mean annual energy usage will be below 16,500 kWh
per household
