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\textbf{College of the Holy Cross, Fall Semester 2018} \\
\textbf{MONT 104N -- Modeling the Environment} \\
\textbf{Midterm Exam, October 26}

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\noindent\textbf{Your Name}: \underline{\phantom{Name Name Name Name Name}}

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\paragraph{Instructions} Please write your answers in the spaces
provided on the following pages, and show work on the test itself. \textbf{For possible
partial 
credit, you must show work}. Use the back of the preceding
page if you need 
more space for scratch work.



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\noindent\textbf{Please do not write in the space below}


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Problem & Points/Poss    \strut \\

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I  & \hfil/\  20\hfil \strut \\

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II  & \hfil/\  30\hfil \strut \\

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III  & \hfil/\  20\hfil \strut \\

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Essay  & \hfil/\  30\hfil \strut \\


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Total   & \hfil/100\hfil \strut \\

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Do all work on these sheets.  You may use the back sides if necessary. 
There are 100 possible points (distributed as indicated in the questions).
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\noindent
I.  In discussing amounts of water needed for irrigation of farmland,
a common unit of volume is the acre-foot.  One acre-foot of water is
the amount of water necessary to cover a perfectly flat field one acre in 
area, to a depth of one foot.  Using the information below, answer questions A and B.
\begin{itemize}
\item 1 yard $=$ 3 feet
\item 1 acre $=$ 43560 square feet
\item 1 meter $\doteq$ 3.28 feet
\end{itemize}
\begin{enumerate}
\item[A.] (10)  How many cubic yards (${\rm yd}^3$) of water are there in one acre-foot?
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\item[B.] (10)  How many cubic meters (${\rm m}^3$) of water are there in one acre-foot?
\end{enumerate}
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II.  According to the 2014 Advancing Sustainable Materials Management factsheet produced by 
the U.S. Environmental Protection Agency, the total amounts of various types of materials 
produced, recycled, and disposed of in landfills in the U.S. were as follows.  
All figures are in units of millions of tons.
$$\matrix{ {\bf Category} & {\bf Produced} & {\bf Recycled} &{\bf Landfilled}\cr
           {\rm Paper\ and\ paperboard} & 68.61 & 44.40 & 19.47\cr
           {\rm Metals} & 23.26 & 7.90 & 12.82\cr
           {\rm Plastics} & 33.25 & 3.17 & 25.10\cr
           {\rm Glass} & 11.48 & 2.99 & 7.04 \cr
           {\rm Others} & 4.44 & 1.29 & 2.58 \cr}$$  
\begin{enumerate}
\item[A.]  (15)  Construct a bar chart showing the \emph{percentages} of the amounts produced
that are \emph{recycled} for each of these materials. 
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\item[B.]  (5)  Which material is landfilled most, proportionally (that is, considering the landfilled amount
as a fraction of the amount produced)?  Explain.
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\item[C.]  (10)  What percentage of the total weight of these classes of materials produced
is recycled?   What percentage of the total produced is landfilled?  
\end{enumerate}
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\noindent
III.   
\begin{enumerate}
\item[A.]  (11) In 2010, $2.74 \times 10^5$ hybrid and electric vehicles were sold in
the US.  In 2015, the number was $4.98 \times 10^5$.  Construct a linear model for the 
number of hybrid vehicles sold as a function of $t = $ years after 2010 using this information.
What does your model predict about the number of hybrid and electric vehicles sold in 2018?
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\item[B.]  The following spreadsheet shows more complete data 
for the total number of hybrid (and electric) vehicles sold for each year from 2010 through 2015.
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Answer each of the following questions based on this information:
\begin{enumerate}
\item[1.]  (3)  Based on the scatter plot, the $R^2$ (``coefficient of determination'') is
probably:
\leftline{ between $0$ and $.25$ $\underline{\qquad\qquad\qquad}$}
\leftline{ between $.25$ and $.5$ $\underline{\qquad\qquad\qquad}$} 
\leftline{ between $.5$ and $.75$ $\underline{\qquad\qquad\qquad}$} 
\leftline{ between $.75$ and $1$ $\underline{\qquad\qquad\qquad}$} 
\item[2.]  (3) The least squares regression line for this data set would
have a slope $m$ about:
\leftline{ $m = 60000$ $\underline{\qquad\qquad\qquad}$}
\leftline{ $m = -60000$ $\underline{\qquad\qquad\qquad}$}
\leftline{ $m = 30000$ $\underline{\qquad\qquad\qquad}$}
\item[3.]  (3)  What are the units of the slope?  
\end{enumerate}
\end{enumerate}
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\noindent
{\it Essay} (30)
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Why is there great interest in creating synthetic bacteria and other single-cell
organisms?  For what jobs might they be useful?  On the other hand, what 
potential dangers have people suggested in this kind of work?  Considering 
{\it Frankenstein} as a warning, is this something we should be pursuing with our
technology?  Are the potential good effects enough to outweigh the possible dangers?    
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