A Sample of 12 Items Yields $\bar { X }$ = 485 Grams and S = 1

Multiple Choice

A sample of 12 items yields $\bar { X }$
= 48.5 grams and s = 1.5 grams.Assuming a normal distribution,construct a 90 percent confidence interval for the population mean weight.

A) $\left[ \begin{array} { l l } 47.722 & 49.278\end{array} \right]$
B) $[ 47.788$$\quad$$\quad$$49.212 ]$
C) $\left[ \begin{array} { l l } 45.806 & 51.194\end{array} \right]$
D) $[ 47.865$$\quad$$\quad$$49.135 ]$