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exam 2 answers - Psychology 2801 Practice Exam Answers 1) A...

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Psychology 2801 Practice Exam Answers 1) A researcher would like to test the effectiveness of a newly developed growth hormone. The researcher knows that under normal circumstances laboratory rats reach an average weight of μ = 950 grams at 10 weeks of age. The distribution of weights is normal with σ = 30. A random sample of 30 newborn rats is obtained, and the hormone is given to each rat. When the rats in the sample reach 10 weeks old, they are weighed. The mean weight for this sample is 974 grams with a standard deviation of 27. The researcher wants to know if this sample of 30 rats differs from the general population. a) Test this hypothesis using an α of .05. H 0 : μ = 950 H 1 : μ 950 4.38 = = 30 30 950 974 z z crit using an α of .05 is ± 1.96 z obt > z crit Since z obt (4.38) > z crit (1.96), I reject the null that this sample of rats came from the general population. Since the mean for this sample (974) was higher, there was some evidence that these rats scored higher than the general population. 2) To test the effectiveness of a new treatment for depression, a sample is selected from a population with μ = 40. After the treatment is administered to the individuals, the sample mean equaled 46 and the standard deviation equaled 12. The researcher is interested in whether the drug will affect depression scores over time. a) Using an N of 4, is there sufficient evidence to reject the null? H
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This note was uploaded on 04/11/2008 for the course PSY 2801 taught by Professor Guyer during the Spring '08 term at Minnesota.

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exam 2 answers - Psychology 2801 Practice Exam Answers 1) A...

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