<prompt> Sampling error occurs due to the variation in results-Between one sample and anotherBetween the observations of two individualsDue to the use of many instruments in the studyDue to the multiple readings taken on the same instrument  <response>: 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, Parks Textbook of Preventive and Social Medicine, Page no. 913 