Estimated Median equation

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Equation / Last modified by KurtHeckman on 2019/03/14 00:01
`M_(EST) = `
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Asimwefredleroy.Estimated Median equation
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7d7432c1-82d1-11e5-9770-bc764e2038f2

The Estimated Median calculator computes the estimated median based on the Lower Class boundary of the group containing median, the Number of Observations, the cumulative frequency of groups before median group, the frequency of median group and the group width.

INSTRUCTIONS: Enter the following:

  • (L) This is the Lower Boundary
  • (n) Total Frequency
  • (F) This is the cumulative frequency of groups before median group
  • (fm) This is the frequency in group
  • (w) This is the group width

Estimated Median (MEST): The calculator returns the estimated median.

The Math / Science

The formula for the estimated median of a group is:
          `M_(EST)=  L+(((n/2)-F) / fm) ⋅w`
where:

  • MEST = Estimated Median
  • L = Lower Class boundary of the group containing median
  • n = Total Frequency
  • F = cumulative frequency of groups before median group
  • fm = frequency in group
  • w = group width

The Estimated Median of a Group is used to calculate estimated median of a group data. For example

The Median is the mean of the ages of the 56th and the 57th people, so is in the 20 - 29 group:

  • L = 20 (the lower class boundary of the class interval containing the median)
  • n = 112
  • cfb = 20 + 21 = 41
  • fm = 23
  • w = 10
Estimated Median= 20 +  (112/2) − 41 × 10
23
 = 20 + 6.52...
 = 26.5 (to 1 decimal)