Question

The following box plot shows the number of books sold each day at a bookstore for 40 days. How many days did the bookstore sell 2 to 12 books?

A box plot is drawn with end points at 0 and 16. The box extends from 2 to 12 and a vertical line is drawn inside the box at 7

2
4
10
20

Answer 1

Point 2 represents 25% and point 12 represents 75%, the difference is to be converted to a number, which is the one you need

Answer 2

@extrinix

Answer 3

So, we can see in the plot that the first quartile is 2, meaning 25% of the books were sold at 2 books or less. If there was 40 days in total, this makes that \(40\times 0.25\) which is 10, so 10 days would be sold at 2 or fewer.

Now, the third quartile is 12, making 75% of the books be sold at 12 or less,
so \(40\times 0.75\) which is 30,
Now, to get the difference between 12 and 2, you have to subtract 12 (0 to 12) and 2 (0 to 2) from each other (by their day amounts), so
\(30_\text{less than 12}-10_\text{less than 2}\) which gives you:

\(20\), which is the greater than 2, but less than 12 - value.