The higher lead group generally has a lower IQ than the lower lead group.
Work Step by Step
In order to create a box and whisker plot, we use a box and a whisker plot maker online. (To draw one by hand, we draw a line, making the far left point the minimum and the far right point the maximum. Then, we draw a box, where the left side of the box is $Q_1$ and the right side of the box is $Q_3$. Finally we draw a vertical line through the box: this is will be the median.) After doing this, we find that the high lead group has a box that is further left than the low lead group's. Hence the higher lead group generally has a lower IQ than the lower lead group.