Question

The conclusion listed below is based on a relationship between X and Y that is completely spurious. Do the following: (i) Define and explain what spurious relationship means? (ii) Think up a plausible variable, Z, that defines a compositional difference across the values of X. (iii) Describe how Z creates the relationship between X and Y. Students who smoke (X) earn lower grades (Y) than students who do not smoke. Conclusion: Smoking causes poor grades.

Answer 1

• Spurious Relationship
  A spurious relationship is a mathematical relationship in which two variables are associated but not causally related, due to either co-incidence or presence of a certain third unseen factor.
  
  Explanation
  Two factors may be co-related highly. However, there might not be a feasible relationship between the two variables. For example, we may want to study the relationship between rainfall and rise of prices of Gold. As time increases from summer to monsoon, amount of rainfall increases. Also, as time passes by, the prices of gold increases. Thus, there seems to be a positive relationship among them. However, the third factor, time is actually the reason behind this. Hence, Spurious Relationship is explained.
  
  
  
• Here, a third factor maybe the quality of education/social values seved to students.
  
  
• Maybe, the students taken are from lower section of the population and attends some educational institution where studies are not conducted so well. For example, some free schools where teaching is of poor quality.
  
  Also, students going to these institutions are not expected to have much social values and thus resort to smoking.
  
  Again,
  Students from relatively higher section of the population attends some better educational instituition where conduct of studies are high and thus they score more grades.
  
  Also, being from better educational instituition, they will have better social values and thus deter from smoking.
  
  Hence, Z be the quality of education/social values seved to students may act as the third factor.
  
  

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