Our output class is the quality column. Based on that column, we can try to find the average quality of each wine as follows:

print("white mean = ",df_white["quality"].mean())
print("red mean =",df_red["quality"].mean())

And the output of the code is as follows:

white mean = 5.87790935075541
red mean = 5.6360225140712945

As the output says, the average white wine quality is 5.877 and that of red wine is 5.63. The columns in both dataframes are the same.