Which one of the following will be affected by inter-observer variation in epidemiological studies ?

Ans. is 'd' i.e., Reliability o Reliability of a test: Test gives consistent results when repeated more than once on the same individual or material, under the same conditions o Reliability is also known as: Repeatability, Precision or Reproducibility o Reliability of a test depends on : Observer variation: 1) Intra-observer variation: Same observer taking 2 or more readings give varied results 2) Inter-observer variation: Variation between different observers on same subject/ material a Biological (subject) variation: occur due to 3) Changes in parameters observed 4) Variation in perceptions and answers of patients 4) Regression to the mean Errors relating to technical methods: occur due to 1) Defective instruments 2) Erroneous calibrations 3) Faulty reagents 4) Inappropriate/unreliable test