Question: A field researcher is gathering data on the trunk diameters of mature pine & spruce trees in a certain area. The following are the results of his random sampling. Can he conclude, at the .10 level of significance, that the average trunk diameter of a pine tree is greater than the average diameter of a spruce tree?
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Pine trees
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Spruce trees
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Sample size
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40
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70
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Mean trunk diameter (cm)
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45
|
39
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Sample variance
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100
|
150
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[A] The data supports the claim because the test value 2.78 is greater than 1.64.
[B] The data does not support the claim because the test value 1.29 is less than 1.64.
[C] The data does not support the claim because the test value 1.29 is greater than 1.28.
[D] The data supports the claim because the test value 2.78 is greater than 1.28.