Question

How do you find the 1st quartile?

Answer 1

Quartile: Quartile divides a set of observations into 4 equal parts. The first quartile is the value of middle of the first term and the median. The median is the second quartile. The middle value of the median and the last term is the third quartile. Mathematically, they are represented as follows,

1. First Quartile$\left(Q1\right)={\left[\frac{(n+1)}{4}\right]}^{th}$ Term also known as the lower quartile.
2. The second quartile or the 50th percentile or the Median is given as: Second Quartile $\left(Q2\right)={\left[\frac{(n+1)}{2}\right]}^{th}$Term
3. The third Quartile of the $75th$ Percentile $\left(Q3\right)$ is given as: Third Quartile $\left(Q3\right)={\left[\frac{3(n+1)}{4}\right]}^{th}$Term also known as the upper quartile.
4. The interquartile range is calculated as: Upper Quartile – Lower Quartile.

Hence, the first quartile can b calculated as $\mathbf{\left(}\mathit{Q}\mathbf{1}\mathbf{\right)}\mathbf{=}{\left[\frac{(n+1)}{4}\right]}^{\mathbf{t}\mathbf{h}}$