There are 31 children in the class. The lower quartile is the \((31+1)\div 4\) value which is the \(8^{th}\) value, which is \(1\). The upper quartile is the \((31+1)\div 4\,\times 3=24^{th}\) value, ...

We know that for a set of ordered numbers, the median \({Q_2}\), is the middle number which divides the data into two halves. Similarly, the lower quartile \({Q_2}\) divides the bottom half of the ...