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krestik krestik
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9 years ago
A field researcher is gathering data on the trunk diameters of mature pine and spruce trees in a certain area.  The following are the results of his random sampling.  Can he conclude, at the 0.10 level of significance, that the average trunk diameter of a pine tree is greater than the average diameter of a spruce tree?
 
Pine trees
Spruce trees
Sample size
30
35
Mean trunk diameter (cm)
45
39
Sample variance
120
140

What is the test value for this hypothesis test?

Test value:     Round your answer to three decimal places.

What is the critical value?

Critical value:     Round your answer to three decimal places.
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wrote...
9 years ago
A field researcher is gathering data on the trunk diameters of mature pine and 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?


Sample size
Pine 40
Spruce 70
Mean trunk diameter (cm)
Pine 45
Spruce 39
Sample variance
Pine 100
Spruce 150
A. The data do not support the claim because the test value 1.29 is greater than 1.28.   
B. The data support the claim because the test value 2.78 is greater than 1.28.   
C. The data support the claim because the test value 2.78 is greater than 1.64.   
D. The data do not support the claim because the test value 1.29 is less than 1.64.

Answer: B

Running a 2-Sample T-test on the TI-84, you get the following:

Test stat: t = 2.7846
Critcal value: inT(0.90,9504) = 1.29
P-value: 0.0065
Df: 95.04
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