Topic 1:

In Chapter 7, we are learning about probability sampling methods. In the text, there are several examples of the five types of probability sampling methods – simple random, systematic, stratified, cluster and resampling.

For this discussion topic, find a journal article that describes the use of one of these probability sampling methods. Answer the following questions:

1. Describe the situation in the article and identify the population of interest in the article.
2. What type of sampling was used? Explain your answer – how do you know it is this type of sampling?
3. Discuss one of the findings of the article. Are you surprised by the finding?

• Answer all 3 questions completely and pdf copy of article provided: 15 points; your posting must include at least 3 paragraphs, minimum 4 sentences per paragraph.

Topic 2:

In Chapter 9, we are learning about hypothesis testing and Type I and Type II errors. Consider the following scenario:

An auto parts company advertises that its special oil additive will make the engine “run smoother, cleaner, longer, with few repairs.” An independent laboratory decides to test part of this claim. It arranges to have a taxi-cab company’s fleet of 100 cars use the additive, and follows them to see if how many need repairs. At the end of a year, the laboratory will compare the percentage of cars that need repairs to the historical repair percentage.

For this scenario, answer three of the following questions:

1. What kind of study is this? Explain.
2. Will they do a one-tailed or two-tailed test? Explain.
3. Explain in this context what a Type I error means.
4. Explain in this context what a Type II error means.
5. Which type of error would the additive manufacturer consider more serious? Explain.
6. How might you improve this study?

• Answer all 3 questions completely: 15 points; each question answer must include at least 2 sentences