Answer: The interquartile range= 12
Explanation:
From the given the lower quartile
= 42
the middle quartile
= 49
The upper quartile
= 54
We know that the interquartile range is given by:=-
Interquartile range= upper quartile- lower quartile or

⇒

Hence, the interquartile range of the data displayed in this box-and-whisker plot is 12.