1 A statistical survey is a scientific process of collection and analysis of numerical data. Explain the stages of statistical survey. Describe the various methods for collecting data in a statistical survey.
Answer:- Definition of Statistical Survey
A Statistical Survey is a scientific process of collection and analysis of numerical data. Statistical surveys are used to collect information about units in a population and it involves asking questions to individuals. Surveys of human populations are common in government, health, social science and marketing sectors.
Stages of Statistical Survey: Statistical surveys involve two stages namely — Planning and Execution. Figure 2.1 shows the two broad stages of Statistical Survey
Planning a Statistical Survey: The relevance and accuracy of data obtained in a survey depends upon the care taken in planning. A properly planned investigation can lead to the best results with least cost and time. Figure 2.2 gives the explanation of steps involved in the planning stage.
Execution of statistical survey: Controlled methods should be adopted at every stage of carrying out the investigation to check the accuracy, coverage, methods of measurements, analysis and interpretation. The collected data should be edited, classified, tabulated and presented in the form of diagrams and graphs. The data should be carefully and systematically analysed and interpreted.
Collection of Data
Collection of data is the first and most important stage in any statistical survey. The method for collection of data depends upon various factors such as objective, scope, nature of investigation and availability of resources. Direct personal interviews, third party agencies, and questionnaires are some ways through which data is collected.
Primary data : Primary data is the one, which is collected by the investigator for the purpose of a specific inquiry or study. Such data is original in character and is generated by a survey conducted by individuals or a research institution or any organisation.
For Example:
If a researcher is interested to know the impact of a non-meal scheme for school children, he/she has to undertake a survey and collect data on the opinion of parents and children by asking relevant questions. Such a data collected is called primary data.
Collection of primary data is done by a suitable method as per the following:
1. Direct personal observation
2. Indirect oral interview
3. Information through agencies
4. Information through mailed questionnaires
5. Information through a schedule filled by investigators.
Secondary data: Any information, that is used for the current investigation but is obtained from some data, which has been collected and used by some other agency or person in a separate investigation, or survey, is known as secondary data. They are available in a published or unpublished form.
In published form, secondary data is available in research papers, newspapers, magazines, government publication, international publication, and websites. Secondary data is collected for different purposes. Therefore, care should be exercised while using it. The accuracy, reliability, objectives and scope of secondary data should be examined thoroughly before use. Secondary data may be collected either by census or by sampling methods.
Published sources – The various sources of published data are:
- Reports and official publications of international and national organisations as well as central and state governments
- Publications of several local bodies such as municipal corporations and district boards
- Financial and economic journals
- Annual reports of various companies
- Publications brought out by research agencies and research scholars
2 Analysis of daily wages of workers in two organisations A and B yielded the following results:
