ABCTE Professional Teaching Knowledge Practice Exam

What does the interquartile range of a data set represent?

1. The total range of all data points.

2. How spread out the upper half of the data is.

3. The average of the middle numbers in the data set.

4. How spread out the middle of the data is.

The correct answer is: How spread out the middle of the data is.

The interquartile range (IQR) is a measure of statistical dispersion that specifically focuses on the middle 50% of a data set. It is calculated by taking the difference between the third quartile (Q3) and the first quartile (Q1). This range effectively captures the extent of variation within the central portion of the data, providing an understanding of how spread out the values are around the median. By focusing on the middle of the data set, the IQR is particularly useful because it is not influenced by outliers or extreme values that may exist in the overall dataset. Therefore, the interquartile range serves as a robust measure of variability, reflecting the degree of spread among the values that lie between the first and third quartiles. This characteristic makes it an important tool in descriptive statistics for analyzing the central tendency and variability of a data set.