Correlations

  Answer the following questions: (5 points) 1. What is the definition of a correlation and why would a researcher be interested in using this type of analysis? 2. What is another name for a Positive relationship and a Negative relationship? 3. Describe the association between two variables when the relationship is Negative. 4. Is a correlation a good way to determine cause-and-effect? Why or why not? 5. When a large number of cases are examined and a positive relationship is found, what else should one expect to find? Conduct a correlational analysis on the following example (use datafile: Assignment 3 Data.sav) (5 points) Example: A school psychologist is interested in determining if test anxiety is affecting her students’ performance on their exams. She randomly selected 103 students from her school and conducted a correlational analysis to try and answer her question. She hypothesized that as anxiety increases, test performance decreases. Based on this example answer the following questions: (5 points) 1. Why is a correlational analysis the most appropriate technique to test her hypothesis? 2. Use the data set provided and conduct a Bivariate Correlational Analysis using SPSS. Hint: In the Bivariate Correlations dialogue box in SPSS, select Pearson. Create a Simple Scatterplot with Exam Performance on the Y-axis and Exam Anxiety on the X-axis. 3. Observe and briefly explain the trend seen in the Scatterplot (1-2 sentences). 4. What is the strength and direction of the relationship between Performance and Anxiety? 5. Based on these findings, can she infer that one variable Causes the other (i.e., cause-and-effect)? Why or why not? 6. Discuss the findings using Morgan et al. (2002) pp. 33-34.    

Sample Solution

   

Correlation is a statistical measure that quantifies the degree of association between two variables. It tells you how much one variable tends to change along with the other, indicating either a positive, negative, or no relationship. Researchers use correlation analysis to:

  • Explore potential relationships: Identify whether two variables might be linked, sparking further investigation for causal explanations.
  • Predict outcomes: Understand how changes in one variable might predict changes in the other, aiding in forecasting and decision-making.
  • Support causal hypotheses: While not proving causation, a strong correlation can support existing hypotheses about cause-and-effect relationships.

Full Answer Section

   

 Alternative Names for Relationships

  • Positive Relationship: Also called direct relationship, where both variables increase or decrease together (e.g., studying hours and exam scores).
  • Negative Relationship: Also called indirect relationship, where one variable increases as the other decreases (e.g., stress levels and sleep quality).

3. Describing a Negative Relationship

In a negative relationship, as one variable increases in value, the other one decreases in value. Imagine ice cream sales and temperature: when temperatures rise, ice cream sales tend to go up, but conversely, when temperatures drop, ice cream sales typically decline.

4. Correlation and Causation: Not Hand in Hand

No, correlation does not imply causation! Simply because two variables are related doesn't mean one causes the other. There could be a third, unobserved variable that influences both, creating a spurious relationship. For example, both exercise and weight loss might correlate with increased happiness, but the true cause might be improved well-being impacting both lifestyle choices and mood.

5. Positive Relationships and Large Data Sets

When investigating a positive relationship with a large dataset, researchers should generally expect to find:

  • Greater strength of the correlation: A larger sample size provides more data points, potentially strengthening the observed relationship.
  • Increased confidence in the findings: The larger sample size increases the statistical power of the analysis, meaning the results are less likely to be due to chance.
  • Potential for outliers: Even with a strong correlation, some data points might not follow the trend. Analyzing outliers and understanding their influence on the overall results is crucial.

Remember, correlation is a valuable tool for exploring relationships, but it's crucial to interpret findings cautiously and avoid jumping to causal conclusions. Further research and careful consideration of alternative explanations are essential for establishing true cause-and-effect relationships.

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