This GSEB Class 11 Commerce Statistics Notes Chapter 1 Collection of Data covers all the important topics and concepts as mentioned in the chapter.

## Collection of Data Class 11 GSEB Notes

**Origin and Growth of Statistics:**

- From the time of Mauryan empire (321-296 BC) the contribution of India in Statistics has been quite significant.
- During the time of Mughal empire, Akbar (1596-97) mentioned statistical system in ‘Ain-I-Akbari’ written by Abul Fazal.
- The German word ‘Statistik’ was first used by Gottfried Achen Wall in 1749 for analysis of data of the state.
- By 18th century, the term ‘statistics’ was used for systematic collection of data by states.
- Statistics was formally introduced in Encyclopedia Britanica in 1797.
- In 17th and 18th century Laplace (1749- 1827) and Gauss (1772-1855) presented the initial principles on probability.
- In the late 19th and early 20th century Karl Pearson founded Mathematical Statistics. Galton and Karl Pearson used mathematical statistics in Science, Industry and Politics.
- During 1910 and 1920, Gosset and Fisher developed modern statistical science and applied in the fields such as genetics, biometry, psychology, education, agriculture, etc.
- During 1930, role of E. Pearson and J. Neyman had been significant in the development of statistics. After that advanced methods of statistics were developed day-by-day.

**Growth of Statistics in India:**

- Contribution of Prof. P. C. Mahalanobis has been significant in growth of statistics in India. He has founded Indian Statistical Institute – ISI in 1931 at Kolkata. He started for the first time post graduate course in Statistics at Kolkata University in 1941.
- In 1950, Mahalanobis established National Sample Survey – NSS and started data collection. (NSS has been named as National Sample Survey Organisation – NSSO at present.)
- Indian Agriculture Statistics Research Institute – IASRI has contributed a lot in the development of statistics in India.
- Among the various definitions of statistics, the definition given by Croxton and Cowden is ‘Statistics is the science which deals with the collection, analysis and interpretation of numerical data.’
- Now a days, statistics is not only useful for quantitative data but also for qualitative data.
- Statistics is considered as a part of scientific methods. An important branch of statistics is Operations Research-OR, which was used in the military projects during the second world war. The use of OR in industries and for the government cannot be ignored.

**Quantitative Data and Qualitative Data:**

- Population: In statistics, a group of all the units under study is called a population. For example, in population census a group of all citizens of the country is population.
- Population Size: The total number of units in the population is called the size of population. It is denoted by symbol ’N’.
- Finite Population: If the total number of units contained in the population N is countable such a population is called finite population.
- Sample: A set of units selected from the population on the basis of some definite criterion is called sample. For example, a group of 90 students selected at random from the 900 students of a school is sample.
- Sample Size: The number of units in the sample is termed as the sample size. It is denoted by symbol ‘n’. For example, if 30 workers are selected by some statistical method from 300 workers of a factory, then sample size n = 30.
- Variable Characteristics: A characteristic that varies for each unit of population or sample is called variable characteristic. It can be either numerical or non-numerical. If the variable characteristic is non-numerical or qualitative it is called qualitative variable or attribute. If the variable characteristic is numerical, it is called numerical variable.
- Data: A set of all the observations obtained by an inspection of a variable characteristic defined on units of a population or the sample selected from it, is called data.
- Qualitative Data: A set of observations on the attribute is called qualitative data. For example, data on sex of the workers of a factory, level of education, economic condition of parents of students of a school, etc. are qualitative data.

**Primary Data and Secondary Data:**

- Primary Data: The data originally collected by any authorised agency or investigator for the first time is called primary data. For example, the data collected by NSSO of population census of India every ten years are primary data.
- Secondary Data: When an authorised agency or investigator uses the data collected by any other agency or investigator, then such data becomes secondary data for the users. For example, if the planning commission make use of the data collected in population census for economic planning of the country, than for planning commission that data becomes secondary data.

**Methods of collecting Primary Data:**

- Method of Direct Inquiry: An investigator himself collects the data by visiting personally to the field.
- Method of Indirect Inquiry: Instead of an investigator, data is obtained with the help of the third party.

**Method of Questionnaire:**

A questionnaire is prepared by making a list of questions relevant to the object of the study keeping the space between the questions for the answers. The method of collecting data using such type of questionnaire is called method of questionnaire.

There are two ways of collecting data by questionnaires:

- By post and
- By enumerators.

**Secondary Data:**

Sources of Secondary Data:

- Government Publications,
- Semi-government Publications,
- International Publications,
- Reports of Research Organisations,
- Reports of Local self Government Institutions and Autonomous Educational Institutions,
- Publications of Business and Commerce Organisations,
- Newspapers and Periodicals and
- Unpublished Sources.

**Precautions for using Secondary Data:**

Before using secondary data, the following precautions should be taken:

- Data collector and source of data,
- The purpose of collecting data
- The time period of data collected,
- Scope of data, region of data and definitions of different terms
- Whether data is estimated and
- The method of collecting data.