Answer
The graph for frequency distribution with 7 classes is shown below.
Work Step by Step
Data range: $37.9-17.3=20.6$
Bin width (7 classes): $\frac{20.6}{7}=2.94\approx3$
Start point for bin 1: $17.25$ to avoid any data fall on bin walls
Count the frequency in each bin and plot the data.