Complex sentence: The first quartile ("Q" 1) is defined as the middle number between the smallest number and the medociology and finance, the quartiles of a ranked set of data values are the four subsets whose boundaries are the three quartile points.
Split into simpler sentences: The first quartile ("Q" 1) is defined as the middle number between the smallest number and the median of the data set. In applications of statistics such as epidemiology, sociology and finance, the quartiles of a ranked set of data values are the four subsets whose boundaries are the three quartile points.