Question

Governor Cuomo's press conference he just announced that from a sample of 7,500 New Yorker's, 14.3% tested positive for the Covid antibodies. (Note the presence of the antibodies indicates you have been infected with the virus.) The sample was taken in public places, for example at grocery stores, where individuals were asked if they would voluntarily be tested. I believe that the 14.3% infection rate woefully biased. Provide the reason and defined in the text and class notes and an explanation as to the mechanism that has led me to this belief.

Answer 1

The reason is sampling bias

Concept: Sampling bias means that the samples collected are not selected correctly and do not represent the true population parameters. The main reason for its occurrence is that values are either under-reported or over-reported with respect to population parameters

Here in this example, the sample is taken only at the public places and that too from those who were willing to give. The first reason for sampling bias is that not the whole population is at the public place every time. Maybe they are those people who are taking the utmost precautionary measures.

The second reason is individuals are not selected randomly and each individual selected does not have an equal probability of getting infected. Selection bias is the reason for which we can say that 14.3% is heavily biased