The interquartile range is a measure of dispersion used in descriptive statistics that is calculated as the difference between the third and the first quartile. This difference represents 50% of the data. In other words, the interquartile range is the 50% central range of the ordered data.
Therefore the correct answer is the option a:
The interquartile range is the range of the middle 50% of the sorted incomes of the top ten grossing movies.
