What is the difference between the Ist quartile, the IInd quartile, and the IIIrd quartile?
Quartiles are used to describe the distribution of data by splitting data into three equal portions, and the boundary or edge of these portions are called quartiles.
That is,
The lower quartile (Q1) is the 25th percentile.
The middle quartile (Q2), also called the median, is the 50th percentile.
The upper quartile (Q3) is the 75th percentile.