Demand schedule and demand curve
Demand schedule and demand curve are related to the price of the goods and services and Quantity of goods and services. 


Demand schedule :- demand schedule is a list of quantities of a commodity which is purchased by the consumer at different prices. Or a list of quantities of any goods or product there will be both in given market at the given time. In the demand schedule it is mention that such amounts would be bought a different prices it doesn't so what the price is. Another words we can say demand schedule is related to the price of the commodity and the quantity of the commodity, when the price low the larger quantity is to be purchased by the consumer similarly when the price high the smaller quantity to be purchased by the consumer. We can access with the help of Demons schedule that the price of the Goods and the quantity to be bought by the consumer. 
Ex. 


Demand curve:- demand curve is a graphical representation between the price of goods and the quantity of goods that consumer willing and able to buy in the given period of time. 

According to friedman :- as demand curve of a particular group for a particular commodity can be defined as a locus of point each of the shows the maximum quantity of the commodity that will be purchase by the group per unit of time at a particular price it represents and attempt to relate a rate of flow to a price at an instance of time. 



The demand curve slopes downward because as the price of goods or service increases consumer purchase it less or vice-Versa the curve shows the quantity demanded at each price point, and the resulting curve can be used to analyze the behaviour of consumers and make decisions about pricing in production level.