2. Which of the following statements is true?

(A) A parameter is a number that describes some characteristic of a sample.

(B) An unbiased estimator is any statistic that is taken from a sample chosen by

random methods.

(C) A sampling distribution is the distribution of a statistic calculated from all possible

samples of the same size from the same population.

(D) The variability of a population distribution will decrease as the sample size

increases.

(E) A normal approximation can always be used for the sampling distribution of pas

long as the sample size is greater than 30.