Final answer:
A box plot is the best representation for determining where the middle 50% of the data lies because it clearly shows the median, quartiles, and the interquartile range.
Step-by-step explanation:
To determine between which two values 50% of the data will lie, a box plot (also known as a box-and-whisker plot) would be the most suitable representation. A box plot visually displays the median, quartiles, and the interquartile range (IQR), which represents the middle 50% of a data set. Given the nature of a box plot, you can easily identify the first quartile (Q1) and the third quartile (Q3), and thus the IQR can be observed, showing exactly where the central 50% of the data lies.
In the context provided, a box plot would allow us to see the middle 50% with the box representing the data between the first quartile (25th percentile) and the third quartile (75th percentile), giving us the needed insights.