Question: 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 n=25 newborn rats is obtained, and the hormone is given to each rat. When the rats in the sample reach 10 weeks old, each rat is weighed. The mean weight for this sample is M=974.

a. Identify the independent and dependent variables for this study.

b. Assuming a two tailed test, state the null hypothesis in a sentence that includes the independent variable and the dependent variable.

c. Using symbols, stat the hypothesis (H₀ and H₁) for the two tailed test.

d. Sketch the appropriate distribution, and locate the critical region for α=.05.

e. Calculate the test statistic (z-score) for the sample.

F. What decision should be made about the null hypothesis, and what decision should be made about the effect of the Hormone?