upper and lower quartiles?

Question

what is the correct method to calculate the upper and lower quartiles of a set of data, also please include any ways to over complications like if there is an uneven number of data values etc.

Answer 1

Quartiles are the 25% and the 75% of a set of data. We know that the MEDIAN divides a set of data into 2 sub-sets

Lower Quartile (Q1) = middle value of the first sub-set
Upper Quartile (Q3) = middle value of the second sub-set

Let's say that you have a set of data
{ 2, 7, 15, 36, 39, 41, 41, 43, 43, 47, 48 }

-Divide the set of data by getting the median (median = 41)
Set 1 = { 2, 7,15, 36, 39 }
Set 2 = { 41, 43, 43, 47, 48 }

-Hence,
Q1 = 15 (where 15 is the 25% of the data set)
Q3 = 43 (where 43 is the 75% of the data set)