Collection of Data — Economics STD 11 Commerce — Question

Sampling errors refers to the difference between the sample estimate and the actual value of a characteristic of the population. It is the error that occurs when we make an observation from the sample taken from the population. Sampling error may be due to small size of sample or to defective methods of sampling etc.
Non-sampling errors are those which creep in due to human factors which always vary from one investigator to other. Some of the non-sampling errors are :

1. Errors in data acquisition
2. Non-response errors
3. Sampling bias

These errors arise in both census and sample surveys. They are more serious than the sampling errors.