Using a new technique, Hb was estimated in a blood sample. The test was repeated for 10 times. The repos were : 9.5, 9.2, 9.4, 9.6, 9.7, 9.9, 10.2, 10.3, 10.5, 12.1. Accurate value of Hb was estimated by standard tests to be 10.2. The new technique has ?

Ans. is 'b' i.e. low validity and low reliability Validity (Accuracy) o The validity of a test is the extent to which it accurately measures which it purpos to measure. In other words its the ability to show which individuals have the disease in question and which do not. o Validity has two components - sensitivity & specificity. To be truly valid, a test should be highly sensitive, specific and unbiased. In this question the test results are not accurate (accurate value is 10.2) Test has low validity. Reliability (or Repeatability, reproducibility or precision) Reliability or precision or repeatability is the level of agreement between repeated measurements of the same variable i.e. a highly reliable test must give consistent results when repeated more than once on the same individual or material, under the same conditions. In this question test is not showing consistent results --> Test has low reliability.