A random sample of size n has been selected from a normally distributed population whose standard deviation is s. In estimating an interval for the population mean, the t-distribution should be used instead of the z-test if: $\begin{array}{|l|l|}
\hline A&\text { $ n \geq 30 $ and $ \sigma $ is known}\
\hline B&\text {$ \sigma $ is unknown and estimated by $ s $, and the population is normal. }\
\hline C&\text { Population is normal and $ \sigma $ is known.}\
\hline D&\text {None of these choices are correct. }\
\hline
\end{array}$

Question

A random sample of size n has been selected from a normally distributed population whose standard deviation is s. In estimating an interval for the population mean, the t-distribution should be used instead of the z-test if: $\begin{array}{|l|l|}
\hline  A&\text { $ n \geq 30 $ and $ \sigma $ is known}\
\hline  B&\text {$ \sigma $ is unknown and estimated by $ s $, and the population is normal. }\
\hline  C&\text { Population is normal and $ \sigma $ is known.}\
\hline  D&\text {None of these choices are correct. }\
\hline 
\end{array}$

Quizplus · Accepted Answer

The Answer of A random sample of size n has been selected from a normally distributed population whose standard deviation is s. In estimating an interval for the population mean, the t-distribution should be used instead of the z-test if: $\begin{array}{|l|l|}
\hline  A&\text { $ n \geq 30 $ and $ \sigma $ is known}\
\hline  B&\text {$ \sigma $ is unknown and estimated by $ s $, and the population is normal. }\
\hline  C&\text { Population is normal and $ \sigma $ is known.}\
\hline  D&\text {None of these choices are correct. }\
\hline 
\end{array}$

A Random Sample of Size N Has Been Selected from a Normally