City planners believe that larger cities are populated by older residents. To investigate the relationship, data on population and median age in 10 large cities were collected.
$$
\begin{array}{|lcc|}
\hline \text { City } & \begin{array}{c}
\text { City Population } \\
\text { (in millions) }
\end{array} & \text { Median Age } \\
\hline \text { Chicago, IL } & 2.833 & 31.5 \\
\text { Dallas, TX } & 1.233 & 30.5 \\
\text { Houston, TX } & 2.144 & 30.9 \\
\text { Los Angeles, CA } & 3.849 & 31.6 \\
\text { New York, NY } & 8.214 & 34.2 \\
\text { Philadelphia, PA } & 1.448 & 34.2 \\
\text { Phoenix, AZ } & 1.513 & 30.7 \\
\text { San Antonio, TX } & 1.297 & 31.7 \\
\text { San Diego, CA } & 1.257 & 32.5 \\
\text { San Jose, CA } & 0.930 & 32.6 \\
\hline
\end{array}
$$
a. Plot these data on a scatter diagram with median age as the dependent variable.
b. Find the correlation coefficient.
c. A regression analysis was performed and the resulting regression equation is Median Age $=31.4+0.272$ Population. Interpret the meaning of the slope.
d. Estimate the median age for a city of 2.5 million people.
e. Here is a portion of the regression software output. What does it tell you?
Predictor $\quad$ Coef $S E$ Coef $\quad T \quad$ P $\begin{array}{lllll}\text { Constant } & 31.3672 & 0.6158 & 50.94 & 0.000\end{array}$
Popul ation $\begin{array}{llll}0.2722 & 0.1901 & 1.43 & 0.190\end{array}$
f. Using the .10 significance level, test the significance of the slope. Interpret the result. Is there a significant relationship between the two variables?