Optional extension: Frequency density, interpolation and fitted lines
Example 1
classwidth.Howmanyobservationsarerepresentedintotal?Thetabledescribesahistogramwithunequalclasswidths.Frequencydensity=frequency
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Answer: 50
- Multiply density by width for each class.
- 5×4+15×2=50.
Example 2
There are 60 observations. Estimate the median using position 2N and a uniform distribution within its class.
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Answer: 44.5
- Median position =30.
- There are 12 observations before the middle class.
- Move 2430−12=43 of the way across its width 6.
Example 3
classwidth.Howmanyobservationsarerepresentedintotal?Thetabledescribesahistogramwithunequalclasswidths.Frequencydensity=frequency
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Answer: 85
- Multiply density by width for each class.
- 5×5+15×4=85.