Answer
Using the median concept, the interquartile range of the data-set is:
A. 22.
What are the median and the quartiles of a data-set?
The median of the data-set separates the bottom half from the upper half, that is, it is the 50th percentile.
• The first quartile is the median of the first half of the data-set.
• The third quartile is the median of the second half of the data-set.
• The interquartile range is the difference of the third and the first quartile.
From this box plot, we have that:
• The first quartile is of 39.
• The third quaritle is of 61.
Then the IQR is: