Can it show positive when you are negative?

Answer 1

The question is difficult to answer because there is no information on what "it" is. Assuming that it is some sort of test result, the answer is, yes, it is possible. Most (if not all) tests are not 100% accurate and there is a small chance that the result will be a "false positive" as in the case here. Similarly, there is usually also a small probability of a false negative: that is, when the test shows negative when you are positive. Most tests are not perfect, but a trade-off between these two types of errors, with the consequences of the wrong decision being taken into account .