: A sample is a part representing the information world or the whole. Sample survey is a method of collecting data from a sample. In other words, the sample survey is the method of collecting information from a particular part of the information world without collecting information from every element or component. For example, if you want to know the average daily income of rickshaw pullers in Dhaka city, you can get information about the average income of all rickshaw pullers by collecting information about their income from some rickshaw pullers representing all rickshaw pullers without collecting information from all rickshaw pullers and this method is sample survey. In this case, all the rickshaw pullers of Dhaka city are information world or the whole number of rickshaw pullers is a sample. Advantages and Disadvantages of Sample Survey Due to several advantages, data analysis is done by conducting sample survey in practical cases. Advantages: ( i) In order to make a decision about the information world in a short period of time in case of emergency, one has to resort to sample survey. ( ii) In case of lack of manpower or lack of funds for full observation or investigation, it is possible to search the world of information by conducting sample survey at low cost. ( iii) Sample survey requires less time to collect data on many more subjects. ( iv) There are many administrative advantages in sampling survey. Sample survey can be done with a small number of trained people. Any complexity or lack of credibility in collecting information can be easily resolved. ( v) If the whole or information world is infinite, in this case the data must be collected through sample survey. Disadvantages: ( i) It is not possible to get information through sample survey if it is necessary to know information about each unit of aggregate. ( ii) If any one element of the data world is very harmful, then it is difficult to find out information about that element by conducting sample survey. If a particular type of drug produced by a pharmaceutical company gives very harmful results to humans, it is difficult to find out through a sample survey. ( iii) Above all, it is not possible to get a completely accurate idea about the data world through sample surveys, but it is possible to get a closer idea.