The relation of output to changes in the quantity of the variable factor
(labour) can be looked at in three different ways. As the quantity of
labour increases, total output increases, as shown in column 2. The
average product in column 3 is found by dividing the total product in
column 2 by the quantity of labour shown in the corresponding row of
column 1. The marginal product is shown between the rows because it
refers to the change in output from one level of labour input to another.
The curves are plotted from the data in the table. In part (i), the TP curve
shows the total product steadily rising, first at an increasing rate, then at a
