Describe how the goal of an experimental research study is different from the goal for nonexperimental or correlational research. Identify the two elements that are necessary for an experiment to achieve its goal.

Omitting a variable from our model that has a causal effect on our dependent variable always leads to omitted variable bias.   a. False   b. True

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Identifying individuals with a high risk of Alzheimer's disease usually involves a long series of cognitive tests. However, researchers have developed a 7-Minute Screen, which is a quick and easy way to accomplish the same goal. The question is whether the 7-Minute Screen is as effective as the complete series of tests. To address this question, Ijuin et al. (2008) administered both tests to a group of patients and compared the results. The following data represent results similar to those obtained in the study.    7-Minute Screen Cognitive Series 3 11 8 19 10 22 8 20 4 14 7 13 4 9 5 20 14 25 Which statistical test would you select: Answer    H0: Answer H1: Answer What is the coefficient that indicates the strength of the relationship? Answer =Answer What is the standard error? Answer What is the appropriate 95% CI?  [ Answer , Answer ] What is the d-effect size? Answer What is the t-observed? Answer What is the actual p-value? Answer THREE decimal places…

Explain the concept of Quasi-Experiments?

Identifying individuals with a high risk of Alzheimer’s disease usually involves a long series of cognitive tests. However, researchers have developed a 7-Minute Screen, which is a quick and easy way to accomplish the same goal. The question is whether the 7-Minute Screen is as effective as the complete series of tests. To address this question, Ijuin et al. (2008) administered both tests to a group of patients and compared the results. The following data represent results similar to those obtained in the study. Patient 7-Minute Screen Cognitive Series A 3 7 B 7 15 C 4 14 D 5 13 E 7 9 F 5 15 G 11 25 The alternative hypothesis in words and null hypothesis in symbols for a two-tailed test is

The type of study that allows us to draw firm conclusions about the cause-and-effect relationship between two variables is a(n): a. experimental or quasi-experimental design b. experimental design c. correlational or quasi-experimental design d. correlational design

A team of epidemiologists at the Mayo Clinic wanted to find whether there is an association between obesity and cardiovascular disease (CVD). They conducted a prospective cohort study following obese and non-obese individuals who were free of CVD at the beginning of study for five years. The investigators were also interested in assessing age as a potential confounder, effect modifier, or both. Use the data below to answer the accompanying questions.     CVD No CVD Total Obese 10 90 100 Not Obese 35 465 500 Total 45 555 600       CVD No CVD Total Obese 36 164 200 Not Obese 25 175 200 Total 61 339 400   1. Compute the appropriate measure of association for those who were less than age 50.  2. Compute the appropriate measure of association for those who were older or equal to age 50.  3. Compute the crude measure of association?  4. List three attributes that age must satisfy before it could…

The same media consultants decided to continue their investigation of the focal relationship between income and TV viewing habits. In order to confirm the existence of the focal relationship, they decided to control for immigration status by adding a variable measuring the number of each survey respondent's grandparents who were born outside the U.S. The researchers wonder if immigration background could influence both income and TV watching (but they hope this is not true, because it could invalidate the focal relationship). The researchers conduct a multivariate regression by adding a measure of number of grandparents born outside the U.S. to the regression equation presented in Equation 2 of Table 1. The results of the second regression equation are presented in Equation 2 of Table 1. Table 1. OLS Regression Coefficients Representing Influence of Income and Control Variables on Number of Hours of TV Watched per Day     Equation 1 Equation 2 Equation 3 Annual Income…

Identifying individuals with a high risk of Alzheimer’s disease usually involves a long series of cognitive tests. However, researchers have developed a 7-Minute Screen, which is a quick and easy way to accomplish the same goal. The question is whether the 7-Minute Screen is as effective as the complete series of tests. To address this question, Ijuin et al. (2008) administered both tests to a group of patients and compared the results. The following data represent results similar to those obtained in the study:   Patient            7-Minute         Screen Cognitive Tests  A                            3                           11  B                            8                           19  C                          10                           22  D                            8                          20  E                            4                           14  F                            7                           13  G                           4…