<prompt> On 1st day, patients BP is measured by a doctor, which is 13080 mm of Hg. After 3 days, pt is again brought to the hospital while another doctor is on duty. Pt is under same physical emotional state as 3 days ago. Now B.P is measured which is 15097. Which of the following explains this reading ?Leaking of valve, that donot completely encircle the arm.Due to fear of the patient.Due to observer error.Due to instrumental error.  <response>: 3 errors are normally seen in measuring B.P: 1. Subject errors : Reading is disturbed dt fearany emotional stress of the patient. 2. Observer errors : Due to difference in interpreting koratkoffs sounds hearing power of different doctors 3. Instrumental error : Due to any problem in B.P apparatus resulting in false reading. - In the given question, as patients physical emotional state is the same, subject bias is unlikely to occur - As two doctors took the reading at two different times, it point towards observer error as there would be differences bw their hearing acuity interpreting sounds. 