CompTIA Data+ (DA0-002)Data AnalysisHard
A data analyst is working with a dataset of product ratings from customers, where ratings are on a scale of 1 to 10. They want to understand the typical rating, but they notice that the dataset has several extreme outliers—a few very low ratings and a few very high ratings that seem to be anomalies. If the analyst wants a measure of central tendency that is least affected by these outliers, which measure should they choose?
- AMedian
- BMean
- CMode
- DRange
Show answer & explanationAnswer & explanation
Correct answer: A. Median
The median is the most robust measure of central tendency against outliers. Unlike the mean, which is pulled towards extreme values, the median, as the middle value in a sorted dataset, remains unaffected by the magnitude of outliers, only their position.
Why the other options are wrong
- B. The mean is highly sensitive to outliers and would be skewed by the extreme low and high ratings.
- C. The mode is the most frequent rating, but it may not be unique or represent the overall center, especially in continuous or near-continuous data with outliers.
- D. Range is a measure of dispersion, not central tendency, and is highly sensitive to outliers.
Outlier Resistance (Central Tendency)
The ability of a measure of central tendency to remain stable and representative of the data's center despite the presence of extreme values (outliers). The median is highly resistant.
- Median: Most resistant to outliers.
- Mean: Least resistant, heavily influenced by outliers.
- Mode: Generally resistant, but may not be unique or central for all data types.
Memory trick: Median's 'M'iddle position means it's 'M'ost resistant.