Weighted Average vs Simple Average: When Some Observations Should Count More
A simple average treats every observation equally. A weighted average gives more influence to observations representing more money, units, people or another relevant share.
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Nominal vs Real Growth: How Inflation Can Turn “Record Revenue” Into a Smaller Gain
A record revenue figure does not necessarily represent record economic activity. Learn how to calculate inflation-adjusted growth and choose an appropriate price index.
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Average vs Median Price: Which Number Better Describes What People Actually Pay?
The mean captures total spending per purchase, while the median identifies the midpoint of a sorted price distribution. Here is how to calculate both and decide which better represents a market.
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Confidence Interval vs Prediction Interval: Estimating a Mean Is Not Predicting the Next Observation
A confidence interval describes uncertainty about an average, expected value, or parameter. A prediction interval describes uncertainty around a new individual outcome—and is usually much wider.
