What is a quartile?

• A. A division of the total into four segments
• B. A division of the total into four equal parts
• C. The fourth item in a list
• D. A quarter note value

Answer: (B)

Quartiles describe where to split a dataset so it forms four equal-sized groups. When data are ordered from smallest to largest, the quartiles are the cut-points that divide the data into four parts with the same number of observations. There are three quartiles: the first quartile, the median (second quartile), and the third quartile, which correspond to the 25th, 50th, and 75th percentiles. The option phrased as a division of the total into four equal parts captures this idea precisely, since quartiles are about creating four equal groups. The other options refer to a single item, a non-statistical term, or a vague division, which don’t describe what quartiles fundamentally represent.