Harmonic Mean Calculator
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Harmonic Mean
Definition
The harmonic mean is the reciprocal of the arithmetic mean of the reciprocals of a given set of numbers. It's particularly useful for rates and speeds, giving appropriate weights to each value.
Formula
Example: Average Speed
If a vehicle travels at:
- 60 km/h for 100 km
- 40 km/h for 100 km
- 30 km/h for 100 km
The harmonic mean speed is:
This is the correct average speed for the entire journey, accounting for the time spent at each speed.
Comparison of Different Means
Important Relationship:
For any set of positive numbers:
(Equality occurs only when all numbers are the same)
Type | Formula | Example |
---|---|---|
Arithmetic Mean | ||
Geometric Mean | ||
Harmonic Mean |
Arithmetic Mean
Best For:
- Simple averages of quantities
- Calculating central tendency
- Equal weight to all values
- Linear relationships
Common Uses:
- Test scores
- Heights/weights
- Daily temperatures
- Income levels
Limitations:
- Sensitive to outliers
- Not ideal for ratios or rates
Geometric Mean
Best For:
- Growth rates
- Percentage changes
- Ratios and proportions
- Exponential relationships
Common Uses:
- Investment returns
- Population growth
- Interest rates
- Price indices
Limitations:
- Only works with positive numbers
- More complex calculation
Harmonic Mean(Current)
Best For:
- Rates and speeds
- Per-unit quantities
- Reciprocal relationships
- Density measurements
Common Uses:
- Average speed over different distances
- Price per unit calculations
- Density measurements
- Circuit calculations (parallel resistors)
Limitations:
- Only works with positive numbers
- Gives more weight to smaller values
When to Use Each Mean
Use Arithmetic Mean when you need a simple average and all values should have equal weight
Use Geometric Mean when dealing with growth rates, returns, or multiplicative changes
Use Harmonic Mean when working with rates, speeds, or other measures where using reciprocals makes sense
Related Links
Mean, Median, Mode Calculator
Geometric Mean Calculator
Line Chart
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