Explain whether each of the following is possible.
a. A relationship exists in the observed sample but not in the population from which the sample was drawn.
b. A relationship does not exist in the observed sample but does exist in the population from which the sample was drawn.
c. A relationship does not exist in the observed sample, but an analysis of the sample shows that there is a statistically significant relationship, so it is inferred that there is a relationship in the population.