You want to compare a sample average to a population average.The sample population size is 130.The data table is shown below. $$\begin{array} { l c c }
\hline & \text { Test Commercial } & \begin{array} { c }
\text { Population of } \
\text { Commercials }
\end{array} \
\hline \text { Average purchase intent } & 3.9 & 3.1 \
\text { Standard deviation } & ? & ? \
\text { Sample size } & ? & ? \
\hline
\end{array}$$ How many of the question marks represent required pieces of data?
A)1
B)2
C)3
D)4

Question

You want to compare a sample average to a population average.The sample population size is 130.The data table is shown below. $$\begin{array} { l c c } 
\hline & \text { Test Commercial } & \begin{array} { c } 
\text { Population of } \
\text { Commercials }
\end{array} \
\hline \text { Average purchase intent } & 3.9 & 3.1 \
\text { Standard deviation } & ? & ? \
\text { Sample size } & ? & ? \
\hline
\end{array}$$ How many of the question marks represent required pieces of data?
A)1
B)2
C)3
D)4

Quizplus · Accepted Answer

To compare a sample average to a population average, you need the standard deviation of the sample to calculate the standard error. The population standard deviation is not required if you're comparing means. The sample size is given (130), so you don't need it for the sample. The population size is not necessary for this comparison. Therefore, only 2 pieces of data (the sample's standard deviation and the population standard deviation) are required.

You Want to Compare a Sample Average to a Population