Regarding calculating the probability of including a sample unit in a probability sample, which of the following is most accurate?
A) It can be determined with a high level of accuracy.
B) Practically speaking, it may be impossible to calculate the probability precisely.
C) If it cannot be calculated precisely, then the sample is not to be considered a probability sample.
D) Precise estimates are known and may be found in statistical tables.
E) Only professional statisticians can determine the accuracy.
Answer: B) Practically speaking, it may be impossible to calculate the probability precisely.