Sample Survey Methods:
If proposed investigation is done only on a part taken out of universe then it will be known as sample survey. This part of the universe is known as sample. The result obtained by investing a part of the universe should also be applicable in case of that universe. It is not essential to investigate the every individual item of the universe.
By this methods time is saved more over it is economy. It is to be noted that if the universe is small sample survey is not necessary for investigation.
Advantages
Less Time: Since sample is only a part of the population in sample survey considerable time and labor are saved. Time is also saved in collection and processing data. Since volume of data is small.
Less Cost : In sample survey we study only on a part of the population and the total expense of collecting data is less than that required in census methods
Accurate Information : In sampling we can get more accurate information.
Reliable Results : Few statistical errors that might occur can be minimized as the data collected and processed is relatively small. Presence of sampling errors can be estimated and controlled with great precision
Economical Methods : If complete enquiry is not necessary for any investigation then it would be simply a wastage to make the complete enumeration. In that case sampling is to be done.
Scientific : If population is based on hypothesis as in the case of tossing a coin or throwing a dice for any number of times sampling is the only scientific methods of estimating the character of population.
Disadvantage
If the sample is not draw properly the results thus obtained may be files inaccurate and misleading
Chances of sampling errors are great. The investigators personal bias regarding the choice of techniques and drawings of sample may lead to opposite result.
The size of sample may not be sufficient to representative of the universe.
If the universe is small sample survey is unnecessary.
In absence of qualified and trained investigators results obtained from sample survey not be accepted.