To assess how the mean of Aflatoxin PPB varies by Corn Yield, you can pivot the Descriptives table to display the statistics that you want.

In the output window, double-click the Descriptives table to activate it.

From the Viewer menus choose:

Pivot
Pivoting Trays...

Select the Statistics icon (the third element) in the Row tray.

Drag the Statistics icon to the Layer tray.

Close the Pivoting Trays window.

Deactivate the table by clicking outside of its boundaries.

According to U.S. law, a yield is unfit for human consumption if aflatoxin exceeds 20 PPB. The pivoted table makes it clear that in these data, only yields 4, 7, and 8 fall below the 20 PPB cutoff.