In statistics, the collection of data is an essential step for analysis and decision-making. Two important methods used for data collection are census and sample survey. Both methods aim to obtain information about a population, but they differ in their approach, cost, time requirement, and accuracy. A census refers to the complete enumeration of all units of a population. In this method, information is collected from each and every individual, household, or unit belonging to the population under study. Since every element is included, the results obtained from a census are generally more accurate and reliable. For example, the national population census conducted by governments counts every person in the country. The main advantage of the census method is that it provides comprehensive and detailed information about the entire population without relying on estimation. However, it also has several limitations. Conducting a census requires a large amount of time, manpower, and financial resources. It is often impractical when the population is very large or widely dispersed. In addition, by the time the data is collected and processed, the conditions may have already changed. A sample survey, on the other hand, involves collecting information from only a selected portion or subset of the population, known as a sample. The sample is chosen in such a way that it represents the characteristics of the entire population. The results obtained from the sample are then used to make inferences about the whole population. Sample surveys are widely used in social sciences, economics, market research, and public policy studies. Compared with a census, a sample survey requires less time, lower cost, and fewer resources. It allows researchers to study large populations more efficiently. However, the accuracy of a sample survey depends heavily on the method of sampling and the size of the sample. If the sample is not representative, the conclusions drawn may be biased or misleading. The main differences between census and sample survey can be understood through several aspects. In a census, data is collected from every unit of the population, whereas in a sample survey data is collected only from selected units. A census provides complete and detailed information, while a sample survey provides estimates based on a portion of the population. The cost and time required for a census are much higher compared to a sample survey. A census is suitable when the population size is small or when