**Question:** Inés works at an animal shelter and has to weigh each of the dogs that come in. She records the results of this process in a table (as shown below). Construct a frequency polygon of Inés’ data

**Solution:** Firstly, we need to complete the midpoints column. Each of these groups fall between multiples of 10, so the midpoints shouldn’t be too difficult to find. The result is the table below.

Now, plotting the midpoints on the x-axis and the frequency values on the y-axis then joining the points with straight lines, we get the frequency polygon shown below.