Quiz 1 SOLUTIONS. A. Simple Random B. Stratified C. Convenience D. Cluster

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1 1. I recently (March 29) got an from Lee Thornton, who is the Interim President of CBC. Apparently, this spring CBC will participate in the Community College Survey of Student Engagement (CCSSE), a national student survey focused on teaching, learning, and retention in community colleges. A certain number of spring quarter classes will be randomly selected, and then the CCSSE will be given to the students in those classes. What type of sampling does this best represent? If you look at the types of sampling on p. 21 of the Chapter 1 Handouts, this is clearly an example of Cluster sampling. We are dividing the population into clusters (i.e. classes), randomly selecting some of them, then choosing all of the members in each cluster (class). Note: as you can imagine, I am VERY eager to see if our class gets selected for the survey! I even thought about responding to the to see if we could be included, but I realized that would totally take away from the randomness of the survey. A. Simple Random B. Stratified C. Convenience D. Cluster Number 2 is short answer, and you need to give me two pieces of information: (i) Observational study, or designed experiment? (ii) A brief explanation of your answer. 2. There has been much research and discussion in recent years about whether or not childhood vaccines are linked to autism. According to the CDC (Centers for Disease Control and Prevention), the studies have shown that there is no link between receiving vaccines and developing ASD (autism spectrum disorder). (i) Do you think that this research is more likely to be based on observational studies, or on designed experiments? (ii) Briefly explain and justify your answer. Page 1

2 (i) Clearly this had to be based on observational studies, collecting data that already existed from children who had either been vaccinated or not. (ii) A designed experiment implies that they are applying a treatment, and in this case the treatment would be basically requiring parents to vaccinate their children or not. Obviously this is not ethical, and researchers would never require that parents NOT vaccinate their children, as it clearly could endanger the children. Therefore, they must be collecting data that is already available. 3. Refer to Attachment 1, which gives a brief newspaper article about a recent study, and also some information about the study methodology. In particular, consider the statement in the first paragraph, A majority of young Americans view Donald Trump s presidency as illegitimate, including about three-quarters of black people and almost half of white. Does that statement represent descriptive statistics, or is it an inferential statement? This statement is clearly inferential, because it refers to a majority of young Americans. In gathering the data, they did not talk to ALL young Americans, they only talked to a sample. From the sample results, they are inferring that all young Americans feel that way. A. Descriptive B. Inferential C. No idea. D. None of the above. 4. Refer again to the study in Attachment 1. Which of the following best describes the target population for the study? As clearly described in both the newspaper article and the Study Methodology, the target population is adults from ages years. Page 2

3 A. The total of 1,833 people who were interviewed between February 16 and March 6, B. All young American adults, ages years. C. All American adults, ages 18 and older. D. None of the above. 5. Refer to Attachment 2 (two pages total), which gives a newspaper article about a recent study. Which of the following is an explanatory variable for this study? The explanatory variable is the education levels of middle-age white Americans. The whole point of the study was to address how differences in education levels are affecting the various outcomes in the lives of middle-age white Americans. So all of the other possible answers given below are possible response variables (the variable of interest), including death rates, marriage status, and suicide rates. The point was to see how does education level affect those outcomes. A. Education levels of middle-age white Americans. B. Death rates of middle-age white Americans. C. Marriage status of middle-age white Americans. D. Suicide rates of middle-age white Americans. Page 3

4 Attachment 1 Information for Questions 3 and 4 Source of article: Tri-City Herald, March 19, 2017 Source for methodology information: Trump-memo-Final-Draft.pdf Retrieved 4/6/2017 Page 4

5 Attachment 2 Information for Question 5 (two pages total) Source of article: Tri-City Herald, March 24, 2017 Page 5

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