What distinguishes a probability sample from a non-probability sample in the context of discussing population parameters? a. A probability sample relies on random selection, while a non-probability sample does not ensure randomness. b. A non-probability sample is used to calculate the population parameter directly, while a probability sample is not. c. A non-probability sample summarizes the population mean, while a probability sample does not. d. A probability sample includes every member of the population, while a non-probability sample does not