Question

Instructions: Write your responses to the following 5 questions for at least 5 of the 7 example news stories about correlational studies:

1. Identify X and describe how it is being measured
2. Identify Y and describe how it is being measured
3. State the direction of the correlation (+ or –)
4. Identify a possible Z (third) variable
5. Fully interpret the relationship between X and Y (in plain English)

Example 2: Proximity to freeway associated with autism

Living near a freeway may be associated with increased risk of autism, according to a new study. The study examined the locations where the children's families' lived during the first, second and third trimesters of their mothers' pregnancies, and at the time of the baby's birth and looked at the proximity of these homes to a major road or freeway. Risk of autism diagnosis was also evaluated within each geographic location (neighborhood). The link between proximity to a freeway and autism risk was not altered by adjustment for child gender or ethnicity, maximum education in the home, maternal age, or prenatal smoking.

Answer 1

1. Here, X is the proximity to freeway (locations), by asking questions to the family, the variable can be measured.

2. Here, Y is Risk of autism, the variable depends on the proximity to freeway, therefore by measuring X variable we can measure Y.

3. Here the direction of the correlation is positive (+) bewteen X and Y.

4. A possible z variable may be geographic location (neighbourhood), the same can be measured by proper investigation.

5. Overall the study is emperical. We need to conduct questionnaire survey and a detailed investigations. Based on the information, we get that the relationship between X and Y is positively correlated. If proximity to freeway is increased, the risk of autism can be increased. Based on the questionnaire survey, we can design linear model between X and Y, an then by using linear regression, we can obtain the effect of X on Y.