# EXERCISE 17

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**Topic 2: Q 1**

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**Explain the importance of random sampling. What problems/limitations could prevent a truly random sampling and how can they be prevented?**

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**Topic 2: Q 2**

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**Explain each sampling technique discussed in the ???Visual Learner: Statistics??? in your own words, and give examples of when each technique would be appropriate.**

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**EXERCISE 17 **

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**What are the assumptions for conducting a paired or dependent samples t -test in a study? Which of these assumptions do you think were met by the Lindseth et al. (2014) study? **

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**1.???????????????? ****In the introduction, Lindseth et al. (2014) described a ???2-week washout between diets.??? What does this mean? Why is this important? **

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**2.???????????????? ****What is the paired t -test value for mood (irritability) between the participants ??? consumption of high- versus low-aspartame diets? Is this result statistically signi???cant? Provide a rationale for your answer. **

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**4. State the null hypothesis for mood (irritability) that was tested in this study. Was this hypothesis accepted or rejected? Provide a rationale for your answer.**

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**5.???????????????? ****Which t value in Table 2 represents the greatest relative or standardized difference between the high- and low-aspartame diets? Is this t value statistically signi???cant? Provide a rationale for your answer.**

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**6.???????????????? ****Discuss why the larger t values are more likely to be statistically signi???cant. **

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**7.???????????????? ****Discuss the meaning of the results regarding depression for this study. What is the clinical importance of this result? **

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**8.???????????????? ****What is the smallest, paired t -test value in Table 2? Why do you think the smaller t values are not statistically signi???cant? **

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**9.???????????????? ****Discuss the clinical importance of these study results about the consumption of aspartame. Document your answer with a relevant source. **

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**10.???? ****Are these study ???ndings related to the consumption of high- and low-aspartame diets ready for implementation in practice? Provide a rationale for your answer. **

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