Levels of carbon dioxide \(\left(\mathrm{CO}_{2}\right)\) in the atmosphere are
rising rapidly, far above any levels ever before recorded. Levels were around
278 parts per million in 1800 , before the Industrial Age, and had never, in
the hundreds of thousands of years before that, gone above 300 ppm. Levels are
now over 400 ppm. Table 2.31 shows the rapid rise of \(\mathrm{CO}_{2}\)
concentrations over the 50 years from \(1960-2010\), also available in
CarbonDioxide. \(^{73}\) We can use this information to predict
\(\mathrm{CO}_{2}\) levels in different years.
(a) What is the explanatory variable? What is the response variable?
(b) Draw a scatterplot of the data. Does there appear to be a linear
relationship in the data?
(c) Use technology to find the correlation between year and \(\mathrm{CO}_{2}\)
levels. Does the value of the correlation support your answer to part (b)?
(d) Use technology to calculate the regression line to predict
\(\mathrm{CO}_{2}\) from year.
(e) Interpret the slope of the regression line, in terms of carbon dioxide
concentrations.
(f) What is the intercept of the line? Does it make sense in context? Why or
why not?
(g) Use the regression line to predict the \(\mathrm{CO}_{2}\) level in \(2003 .\)
In \(2020 .\)
(h) Find the residual for 2010 . Table 2.31 Concentration of carbon dioxide in
the atmosphere
$$\begin{array}{lc}\hline \text { Year } & \mathrm{CO}_{2} \\
\hline 1960 & 316.91 \\
1965 & 320.04 \\\1970 & 325.68 \\
1975 & 331.08 \\\1980 & 338.68 \\\1985 & 345.87 \\\1990 & 354.16 \\
1995 & 360.62 \\\2000 & 369.40 \\
2005 & 379.76 \\\2010 & 389.78 \\
\hline\end{array}$$