The values of systolic BP in a given data are 120, 120, 130, 120, 110, 110, 200. Which of the following will be best to used for central tendency in the given data?
## **Core Concept**
The question tests the understanding of measures of central tendency, specifically in the context of a dataset that may contain outliers. Measures of central tendency include mean, median, and mode, each providing different insights into the dataset's characteristics.
## **Why the Correct Answer is Right**
The correct answer, , is the median. The median is the middle value in a dataset when it is ordered from smallest to largest. If there is an even number of observations, the median is the average of the two middle numbers. In this dataset, the values are 110, 110, 120, 120, 120, 130, 200. The median here is 120, which is the fourth value when the data is arranged in ascending order. The median is best used in this case because the dataset contains an outlier (200), which can significantly affect the mean but not the median.
## **Why Each Wrong Option is Incorrect**
- **Option A:** is incorrect because the mean is sensitive to outliers. The mean of the given dataset is (120 + 120 + 130 + 120 + 110 + 110 + 200) / 7 = 128.57, which does not accurately represent the central tendency due to the outlier 200.
- **Option B:** is incorrect because while it mentions a measure of central tendency, it does not specify which one, making it an unclear choice.
- **Option D:** is incorrect because the mode, which is the value that appears most frequently, is 120. However, the mode does not always reflect the best central tendency, especially in datasets where no value repeats or where there are multiple modes.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that when dealing with skewed data or data that contains outliers, the **median** is often a better measure of central tendency than the mean. This is particularly important in clinical research and practice, where outliers can significantly impact the interpretation of data.
## **Correct Answer:** .