An economy has millions of commodities to produce. It has to decide which goods and services to be produced and that should be in sufficient quantity, as all the goods cannot be produced due to scarcity of resources, e.g. an economy has to decide whether to produce luxury goods or inferior goods, capital goods or consumer goods.
This problem has two dimensions:
(i)Types of goods to be produced.
(ii)Quantity of goods to be produced.

Demand in terms of economics may be explained as the consumers’ willingness and ability to purchase or consume a given item/good. Furthermore, the determinants of demand go a long way in explaining the demand for a particular good.

1. Microeconomics studies economic problems at an individual level. It determines the output and price for an individual firm.  
2. Macroeconomics studies the economic problems at the level of an economy as a whole. It determines an aggregate output and general price level in the economy as a whole.

Sampling is the most less time taking and inexpensive way of collecting data, in this we divide the population into random groups based on geographical habitat, ***, etc or make stratas for the simulation of final statistical results.

Giffen goods are special kind of goods on which the consumers spends most of his income and their demand rises with an inrease in price and demand falls with decrease in price level. For example when the prices of jowar, bajra reduces, then the consumer tends to consumer less of those items and consume superiror goods such as wheat and rice. This is an exceptional case which is against the law of demand. This is because a fall in price of inferior goods increases the real income which reduces demand for inferior goods as consumer prefer to shift to superior goods.

Discrete Variable: A discrete variable is one which increases in jumps or in complete numbers. For example, there can't be 2.4 workers in a factory. They can be 1, 2, 3, 4 and so on. Similarly, a factory can't have 4.8 or 2/7 machines. It will be in complete numbers like 1,2,3,4, and soon. Such variable are called discrete variable. Some other examples of discrete variable are number of workers in a factory, number of machines purchased, number of children etc.

Continuous Variable: Those variables which can assume any value in a given range and which increase continuously and not in jumps are called continuous variable. For example, weight of a person can be 45.234kg, it can take any value within a range. No one gains weight in jumps. It increases in continuity. Other examples are height, income etc.Continuos Variable always lies in a particular interval or range .For instance, height of a child is 3.5 metres which lies between 3 and 4.So, here the interval is equal to( 3,4).

Economy encompasses all activities related to production , consumption and trade of goods and services in an area. It is a system which provides people with the means to work and earn living.

Scope and importance of Statistics:

1. Statistics and planning: Statistics is indispensable into planning in the modern age which is termed as “the age of planning”. Almost all over the world the govt. are re-storing to planning for economic development.

2. Statistics and economics: Statistical data and techniques of statistical analysis are immensely useful in solving economic problem such as determination of wages and price, time series analysis, demand analysis.

3. Statistics and business: Statistics is an responsible tool of production control. Business executive are relying more and more on statistical techniques for studying the much and desire of the valued customers.

Understanding of change in the magnitude of the problem overtime