Which of the Following Statements Are Not True?
A) to Construct

Which of the following statements are not true?

A) To construct an $\bar { X }$
Chart, there are two different commonly used methods for estimating the unknown process standard deviation $\sigma$
; one based on the k sample standard deviations and the other on the k sample ranges.
B) In the case of a normal population distribution, the estimator of the unknown process standard deviation $\sigma$
Based on sample standard deviations S is more efficient than that based on the sample range.
C) The sample standard deviation S is an unbiased estimator of the population standard deviation $\sigma$
; that is, E(S) = $\sigma$
)
D) All of the above statements are true.
E) None of the above statements are true.