"Sampling error" occurs due to the variation in results-
Taking repeated samples from the same population will result in a difference in the results obtained between samples; this is called SAMPLING ERROR. It occurs because data was gathered between samples rather than from the entire population. Ref: 25th edition, Park's Textbook of Preventive and Social Medicine, Page no. 913
Between one sample and another
Between the observations of two individuals
Due to the use of many instruments in the study
Due to the multiple readings taken on the same instrument
Epidemiology