Quartiles for grouped data

Use this calculator to find the Quartiles for grouped (frequency distribution) data.

Quartiles Calculator (Grouped Data)
Type of Freq. Dist. DiscreteContinuous
Enter the Classes for X (Separated by comma,)
Enter the frequencies (f) (Separated by comma,)
Results
Number of Obs. (N):
First Quartile : ($Q_1$)
Second Quartile : ($Q_2$)
Third Quartile : ($Q_3$)

Quartiles for grouped data

$$ \begin{aligned} Q_i=l + \bigg(\frac{\frac{iN}{4} - F_<}{f}\bigg)\times h; \quad i=1,2,3 \end{aligned} $$

where

  • $l :$ the lower limit of the $i^{th}$ quartile class
  • $N=\sum f :$ total number of observations
  • $f :$ frequency of the $i^{th}$ quartile class
  • $F_< :$ cumulative frequency of the class previous to $i^{th}$ quartile class
  • $h :$ the class width

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