Errors in Statistical Data In sample surveys there are two types of error that can occur: sampling error which arises as only a part of the population is used to represent the whole population and; non-sampling error which can occur at any stage of a sample survey. It is important to be aware of these errors so that they can be minimized. Sampling error Sampling error is the error we make in selecting samples that are not representative of the population. Since it is practically impossible for a smaller segment of a population to be exactly representative of the population, some degree of sampling error will be present whenever we select a sample. It is important to consider sampling error when publishing survey results as it gives an indication of the accuracy of the estimate and therefore reflects the importance that can be placed on interpretations. If sampling principles are carefully applied within the constraints of available resources, sampling error can be accurately meas