What is one of the distinctions between a population parameter and a sample statis- tic? A. A sample statistic changes each time you try to measure it, but a population parameter remains xed. B. A population parameter changes each time you try to measure it, but a sample statistic remains xed across samples. C. The true value of a sample statistic can never be known but the true value of a population parameter can be known. D. A population parameter is only based on conceptual measurements, but a sam- ple statistic is based on a combination of real and conceptual measurements.