Six measurements were made of the magnesium ion concentration (in parts per million, or ppm) in a city's municipal water supply, with the following results. It is reasonable to assume that the population is approximately normal
$\begin{array}{llllll}
\hline 175 & 177 & 175 & 180 & 138 & 138 \
\hline
\end{array}$
Construct a $90 \%$ confidence interval for the mean magnesium ion concentration.
A) $( 145.7,182.0 )$
B) $( 147.3,180.4 )$
C) $( 161.2,166.4 )$
D) $( 161.0,166.7 )$

Question

Six measurements were made of the magnesium ion concentration (in parts per million, or ppm) in a city's municipal water supply, with the following results. It is reasonable to assume that the population is approximately normal
 $\begin{array}{llllll}
\hline 175 & 177 & 175 & 180 & 138 & 138 \
\hline
\end{array}$
Construct a $90 \%$ confidence interval for the mean magnesium ion concentration.
A) $( 145.7,182.0 )$
B) $( 147.3,180.4 )$
C) $( 161.2,166.4 )$
D) $( 161.0,166.7 )$

Quizplus · Accepted Answer

The correct confidence interval is calculated using the sample mean and standard deviation, along with the t-distribution for a 90% confidence level with 5 degrees of freedom.

Six Measurements Were Made of the Magnesium Ion Concentration (In 175177175180138138\begin{array}{llllll}\hline 175 & 177 & 175 & 180 & 138 & 138 \\\hline\end{array}175​177​175​180​138​138​​

Six Measurements Were Made of the Magnesium Ion Concentration (In $\begin{array}{llllll}\hline 175 & 177 & 175 & 180 & 138 & 138 \\\hline\end{array}$