The law of demand is a fundamental principle of economics which states that at a higher price consumers will demand a lower quantity of a good. Demand is derived from the law of diminishing marginal utility, the fact that consumers use economic goods to satisfy their most urgent needs first. Demand Schedule. The Law of Demand states that when the price of a commodity falls, its demand increases and when the price of a commodity rises, its demand decreases; other things remaining constant. Thus, there exists an inverse relationship between price and quantity demanded of a commodity.

The main advantage of cumulative percentage over cumulative frequency as a measure of frequency distribution is that it provides an easier way to compare different sets of data. Cumulative frequency and cumulative percentage graphs are exactly the same, with the exception of the vertical axis scale.

Sole Proprietorship

Sole proprietorship means a business owned, financed and controlled by a single person who is recipient of all profit and bearer of all risks.

It is SUITABLE IN AREAS OF PERSONALISED SERVICE like beauty parlour, hair cutting saloons & small scale activities like retail shops.

Yes i consider my self as a consumer. Consumers are the actual buyers or clients who purchase goods and services. In my daily routine spending whether in the shops, restraunt, and any other place of exchange of goods and service is an act reffered as consuming. this justifies me as a consumer.

Scarcity of water , scarcity of food , scarcity of electricity,scarcity of education, scarcity of technology,scarcity of sanitation etc

My wants include: 

(i) Food

(ii) Shelter

(iii) Clothing

(iv) Technology

Out of all these things, I can acquire most however, having the latest form of technology is not possible because there are unlimited wants but limited resources. People desire a lot of things but they do not have the resources to fulfill them. 

qualitative data : 

beauty , intelligence ,  ability to sing , learn skills

quantitative data : 

 income earned ,  marks in a subjects

Quantitative Data : We havequantitative data, if the variables can be measured in numerical terms. For example, daily temperature, height and weight of individuals, price and income, etc. are quantitative variables. Their values can be expressed numerically.

Qualitative Data : Sometimes, it is not possible to measure variables numerically, in the same straight forward manner as heights and weights of individuals, or prices of commodities, or income of individuals. For example, attitudes of people to a political system, intelligence of individuals and their aptitudes towards music and art, beauty of individuals or some objects (like flowers, gardens etc.) cannot be numerically measured. However, we may rank them according to the quality of their attributes.

Following are the functions of statistics :
I. Presentation of facts in figures :Statistics presents the various facts and figures, in such a manner so that various complicated facts become easy, brief and concrete and they may be understood easily. In it, facts are presented through diagrams and graphs, which are useful to a common man also.
2. Establishment of relationship : With the help of statistical methods (correlation), relationship between two or more facts may be established. It may be find out that these facts have any relationship or not, what is the direction and degree of relationship between them etc.
3. Comparison : Two or more effects may be compared with the help of statistics. Various averages, rates, percentages and coefficients are used for this purpose.
4. Interpretation of problems : With the help of statistical devices, interpretation of various problems may be done. For example by collecting the data of unemployment among educated persons, the nature of employment problems among them may be interpreted.
5. Formation of laws and principles of other sciences : Statistics helps to other social and natural sciences in forming the laws and with its help the various rules and principles of those sciences may be tested.
6. Helpful in deciding the policy : With the help of statistics various policy decisions may be taken logically and successfully. For example price policy, export-import policy etc.

 The Marginal Rate of Substitution can be defined as the rate at which a consumer is willing to forgo a number of units good X for one more of good Y at the same utility. The Marginal Rate of Substitution is used to analyze the indifference curve. 

It represents economic growth. Economic growth is an increase in what an economy can produce if it is using all its scarce resources. An increase in an economy's productive potential can be shown by an outward shift in the economy's production possibility frontier (PPF).

Human wants are unlimited but the means or resources to satisfy those wants are limited. With the available resources, all human wants cannot be satisfied. This gives rise to the problem of scarcity.

Economics is concerned with the allocation of scarce resources for the satisfaction of unlimited wants of humans under the conditions of scarcity.

 Scarcity is a universal problem and is faced by all economies. Thus one of the main reasons for studying economics is Scarcity and how resources can be optimally utilised to satisfy the wants of people. Thus we can say that scarcity is the undercurrent of economics.

World bank prepares a report on the basis of per capita income only . It is a narrow concept as World bank takes into account only the income which does not tell every thing about a nation. On the other hand UNDP takes education health life expectancy etc as the base of its report. Hence it is a broad concept as it accounts for all the important components of human development.

Yes,economics in a very basic sense is optimization given the constraints. Scarcity is the biggest and real constraint of our lives.Lets understand with an example,suppose everybody has a lot of money,a lot to buy anything.What would the world look like?Nobody's going to work,no production,no costs,no profits,no exchange rates,no trade,simply there would be no need of any of the economic agents,economic concepts.So,no economics would exist.

Whereas,in reality we as individuals have our income as constraint and we cannot spend more than that.Same goes for the economy as whole, a country makes policy and plans and talks about efficiency ,only because a country has geographical,social,economic and political constraints and it has to make the best out of what it has got.The central problem of economics deals with optimization given the constraints.So,the logic follows.