For a medical purpose, or more commonly for DNA testing to support evidence.
how would you check that an individual has not taken any medication recently
watch them swallow it
A sample of blood would be taken for culture to determine whether the bacteria have entered the bloodstream. A biopsy (removal of a piece of infected tissue) sample may be taken for culture to identify which type of bacteria is causing the infection.
A core sample would have to be taken to determine its age
By visiting the DMV you can take a look at different sample tests. Before the actual test is taken it is best to look through the sample tests first to unsure that you know what you can expect.
In this context, ( s^2 ) would refer to the sample variance of the salaries of the 66 employees taken from the population of 820 employees. It is a measure of how much the salaries of these sampled employees deviate from their average salary. This sample variance provides an estimate of the variance of the population, assuming that the sample is representative.
Population
Since you were adopted by another man at age 6 and now go by his surname I don't think you can be considered you biological fathers child in the eyes of the law now. Your biological fathers name is not on your birth certificate. You could try and see if social security would except a DNA sample from your biological fathers other children to prove that you are his child or maybe your biological fathers parents(this would be better) if any of them would do that for you.
There are several websites where an individual can see sample breakfast menus. Examples would include Docstoc, Must Have Menus, Pine Crest Inn, and English BB.
I am sure if a baby's parenting is in question, then a paternity test would need to be taken to find out for sure which person is the biological father.
It is a physical change. Any change in state or temperature is only physical unless it causes the atoms in the molecules to separate or rearrange themselves. In the case of freezing a biological sample, the point is to preserve it as it is, so the change would only be physical.
When a population is too large, then a sample of the population would be taken to determine the information wanted. For example if you wanted to find out the average IQ of Americans you would not want to give every person living in the United States an IQ test, because that would be highly unrealistic, instead you would want to sample a random group of Americans from multiple backgrounds to get an average IQ of Americans.