Final answer:
The average purchase amount per product made by each customer is found by dividing total purchases by total products. This provides a collective average spending on each product across all purchases.
Step-by-step explanation:
When calculating the average purchase amount per product made by each customer, you would take the total purchases and divide by the total products purchased. The correct formula would therefore be: Total purchases / Total products, which corresponds to option (c). This gives us the average amount spent on each product, taking into account all purchases and all products involved.
It is important to note that this calculation gives the average for all customers collectively, and not for each customer individually. The proportion of customers who choose to buy or not buy the product is not directly relevant to this calculation. However, when considering the larger context of business analysis, understanding the proportion of all people who will buy the product and the proportion of the sample who will buy the product could be valuable for strategic decision making.