Jabarkan i    x[i] dari Kuartil dalam bahasa sunda

)- Q2 = 110 (note line 5 has been duplicated

5    110              to illustrate the point)

Or not include the median in either "half":

More precise mathematical formulations are possible: the quartiles of the distribution of a random variable X can be defined as the values x such that:

With these definitions the quartiles in the last example are 106, 110 and 115:

P(X ≤ 106) = 1/3 and P(X ≥ 106) = 7/9;

P(X ≤ 110) = 5/9 and P(X ≥ 110) = 5/9; and

P(X ≤ 115) = 7/9 and P(X ≥ 115) = 1/3.