CompTIA Data+ (DA0-002)Data AnalysisMedium
A data analyst is examining the distribution of customer ages. The data shows a few extremely old customers, causing the distribution to be skewed to the right. The analyst wants to understand the most typical age of a customer without being heavily influenced by these outliers. Which descriptive statistic should they use?
- ARange
- BMean
- CMode
- DMedian
Show answer & explanationAnswer & explanation
Correct answer: D. Median
When data is skewed or contains outliers, the mean can be heavily influenced and pulled in the direction of the skew/outliers, making it a less representative measure of the 'typical' value. The median, being the middle value, is resistant to extreme values and provides a better measure of central tendency in such cases.
Why the other options are wrong
- A. The range is a measure of spread, not central tendency.
- B. The mean is sensitive to outliers and skewness, making it less representative here.
- C. The mode is the most frequent value but might not represent the 'typical' age if the distribution has multiple peaks or a flat peak.
Median's Robustness to Outliers
The median is a measure of central tendency that is resistant to the influence of outliers and extreme values, making it a preferred statistic for skewed distributions.
- Represents the middle value in an ordered dataset.
- Not affected by the magnitude of extreme values, only their count.
- Provides a more accurate 'typical' value for skewed data compared to the mean.
Memory trick: When the data landscape is bumpy with outliers, the Median is the smooth path through the middle.