Which of the following statements is true? a)in statistics, we use the true mean of a population to estimate the mean of a random sample. b)in statistics, we use the mean from a random sample of a population to estimate the true mean of the population. c)in statistics, the value of the mean from a random sample is the same as the true mean of the population. d)in statistics, the value of the mean form a random sample is unrelated to the true mean of the population.