A Sample of 20 Items from a Population with an Unknown

question 76

Multiple Choice

A sample of 20 items from a population with an unknown $\sigma$ is selected in order to develop an interval estimate of $\mu$ . Which of the following is not necessary?

• A)We must assume the population has a normal distribution.
• B)We must use a t distribution.
• C)Sample standard deviation must be used to estimate \(\sigma\).
• D)The sample must have a normal distribution.