In statistics, quartiles are a type of quantiles which divide the number of data points into four parts, or quarters, of more-or-less equal size. The data must be ordered from smallest to largest to compute quartiles. This refers to the box-and-whisker plot.
In this case, the first quartile (Q1) is defined as the 25th percentile, where the lowest 25% data lies below this point. This is known as the lower quartile. To find the lower quartile, you need to first find the median (Q2) based on the data set and then find the middle value between the minimum value and the value of Q2.
