Graph your data in the form of a scatter plot. The demand curve requires that price is on the y-axis and quantity, or in this case, number of people, is on the x-axis.

In economics, a demand schedule is a table that shows the quantity demanded of a good at different price levels.

You can plot your marginal revenue curve on the same graph as your demand curve. For 11 sales, the demand curve shows a price of $4.95 – but the marginal revenue from that 11th sale is $4.45.