Lead time bias is best described as: a)an actually longer survival time for persons identified during a screening program because they were given an effective treatmentb)an apparently lower survival rate among persons screened compared to an unscreened groupc)a similar survival time for persons identified during a screening program relative to persons who are diagnosed by clinical symptomsd)an apparently longer survival time among persons identified during a screening program because they were identified at an earlier stage of their disease

The correct answer is D) An apparently longer survival time among persons identified during a screening program because they were identified at an earlier stage of their disease

Explanation:

In medicine, screening is a method to diagnose diseases even if the person has no symptoms; due to this, screening is related to earlier detection of diseases than traditional diagnosis based on symptoms. Early diagnosis does not imply longer survival time, but it can lead to doctors or individuals to perceive the survival time was longer, this phenomenon is known as lead-time bias.

For example, a person diagnosed with cancer at an early stage when he is 45 years old,  dies at 50 years old, this means his survival time was 5 years. If the same person is diagnosed at 48 years based on symptoms and he dies at 50 it seems the survival time is less (2 years); however, this is biased as the diagnosis did not change the effect of the disease. According to this, lead-time bias can be described as "an apparently longer survival time among persons identified during a screening program because they were identified at an earlier stage of their disease".

answer: tell your parents first, and wait another couple of days. if it gets any worse, then you should call and ask. and you can always take pain meds if need be.

explanation: