2015-08-21
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IX. Read Тext A.
Text A. Sampling
The Sampling Process. Instead of obtaining data from the whole of the material being investigated, sampling methods are often used in which only a sample selected from the whole is dealt with, and from this sample conclusions are drawn relating to the whole. If the conclusions are to be valid, the sample must therefore be made with great care.
The Advantages of Using Sampling Methods. There are a number of advantages to be gained by using sampling methods. Among these advantages may be enumerated the following:
1. The results can be obtained more quickly, for two reasons: the data are obtained more rapidly and can be analysed more quickly. Speed in analysing the data is also possible by analysing a sample of the data before analysing the whole. The analysis of a 1% sample of the last population census was such an example.
2. When the respondents constitute only a small proportion of the population, they are more willing to give detailed information, and because fewer interviewers are required, a much higher quality of interviewer can be employed.
3. Higher-grade labour can be employed on the computing, tabulating, and analysis of the data.
4. Lower costs.
5. The error can be assessed.
6. It is easier to guard against incomplete and inaccurate returns. A sample is often used as a check on the accuracy of complete censuses.
7. When the investigation entails the destruction of the material – e.g. to discover the life of a lamp – sampling methods are the only practical methods to use.
X. Find the passages in the text where the following ideas are expressed:
1. Sampling methods provide advantages such as the speed in analysing the data in obtaining the information about the whole.
2. By using sampling methods one more advantage is gained. It is the detailed information to be obtained and a more higher quality of inteviewer can be employed.
3. A sample is often used as a check on the accuracy of complete censuses.
4. Sampling methods are known to be the only practical methods when the investigation entails the destruction.
