<prompt> Which one of the following will be affected by inter-observer variation in epidemiological studies ?SensitivityPredictive value of the positive testSpecificityReliability  <response>: 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 Inappropriateunreliable test 