Compute Q1, Q2, Q3 from a dataset using the percentile interpolation method.
Quartiles divide an ordered dataset into four equal parts. Q1 is the 25th percentile, Q2 the 50th (median), and Q3 the 75th percentile. This calculator uses the linear interpolation method (R-7).
Qk at position p = (k/4)(n−1), interpolate between floor(p) and ceil(p)
This calculator uses the inclusive (R-7) percentile method with linear interpolation, which matches Excel's QUARTILE.INC function.
Q1 = 25th percentile, Q2 = 50th percentile (the median), and Q3 = 75th percentile. They split the sorted data into four equal-sized groups.