A cardiologist found a highly significant correlation coefficient (r = 0.90, p = 0.01) between the systolic blood pressure values and serum cholestrol values of the patients attending his clinic. Which of the following statements is a wrong interpretation of the correlation co-efficiency observed?
**Core Concept**
The cardiologist observed a strong positive correlation between systolic blood pressure values and serum cholesterol values in his patients. This correlation coefficient indicates a significant linear relationship between the two variables, suggesting that as systolic blood pressure increases, serum cholesterol levels also tend to increase.
**Why the Correct Answer is Right**
The correlation coefficient (r = 0.90) indicates a strong positive linear relationship between systolic blood pressure and serum cholesterol levels. This means that for every unit increase in systolic blood pressure, there is a corresponding increase in serum cholesterol levels. However, correlation does not imply causation. A strong correlation between two variables does not necessarily mean that one variable causes the other.
**Why Each Wrong Option is Incorrect**
* **Option A:** This statement is correct because the correlation coefficient indicates a strong positive linear relationship between the two variables. It is a correct interpretation of the observed correlation.
* **Option B:** This statement is correct because it highlights the limitations of correlation analysis. It is a valid point that correlation does not imply causation, and other factors may contribute to the observed relationship.
* **Option C:** This statement is a wrong interpretation of the correlation coefficient. It implies that a strong correlation between systolic blood pressure and serum cholesterol levels is sufficient to establish a cause-and-effect relationship, which is not the case.
* **Option D:** This statement is a wrong interpretation of the correlation coefficient. It implies that the observed correlation is due to a direct causal relationship between systolic blood pressure and serum cholesterol levels, which may not be the case.
**Clinical Pearl / High-Yield Fact**
Remember that correlation does not imply causation. A strong correlation between two variables does not necessarily mean that one variable causes the other. Other factors, such as confounding variables, may contribute to the observed relationship.
**Correct Answer: C. It implies that a strong correlation between systolic blood pressure and serum cholesterol levels is sufficient to establish a cause-and-effect relationship.