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To see if Solver is available on your
spreadsheet, go to Tools | Add-Ins, and make sure the Solver Add-in is
checked. If it's checked, you should be able to access Solver by going
to Tools | Solver. If the Solver Add-in does not appear as an option,
you'll need to install it from disk. Contact your administrator.
Many of the spreadsheet exercises in this
project focus on estimating parameters for wildlife populations, such as
occupancy, survival rates, and abundance. Gary White and Jim Hines have
developed programs to conduct such analyses, and you'll need to download
them...you can find links to these programs on many different pages in the
Spreadsheet Project, or just Google them. All of the exercises in this
project focus on conducting an analysis first in a spreadsheet. This is to ensure that you understand exactly how parameters are estimated
because all of the equations are revealed. However, when it is time to do an
analysis of "real" data, you'll want to use one of these programs
because estimation methods are superior to that of a spreadsheet, and because
estimates of standard errors are truly a pain to compute in a
spreadsheet. I've also had papers rejected because a reviewer claimed
"You can't do that in a spreadsheet!"
If
you can’t get the bootstrap to run, here’s what you should try first:
Go to Tools | Macro | Macros | Bootstrap | Edit.
Then, with the Visual Basic module active, click References on the
Tools menu,
and then select
the Solver.xla check box under Available References. If
Solver.xla doesn't
appear under Available References, click Browse and open
Solver.xla in the
\Office\Library\Solver\ subfolder.
Terri Donovan (formally, Therese) is the
Assistant Unit Leader for the Vermont Cooperative Fish and Wildlife Research
Unit. She was first introduced to spreadsheet modeling by Rollie
Lamberson (Humboldt State University), and later developed two books (with
Charles Welden) on using spreadsheets to teach basic concepts in ecology,
evolution, and conservation biology. Currently, she is working on three
e-books that teach quantitative methods in these fields. Terri's
research interests are broad and center on the impacts of land use change on
biodiversity (e.g., habitat fragmentation and loss), as well as research
targeted towards species of high conservation priority in the state of
Vermont.
The Vermont Cooperative Fish and Wildlife
Research Unit is part of the U.S. Geological Survey's National Cooperative
Fish and Wildlife Research Units program. There are 40 units across the
U.S. The Vermont Unit is home to two scientists (Donna Parrish, Unit
Leader-Fisheries) and Terri Donovan (Assistant Unit Leader - Wildlife).
Unit scientists work with the Vermont Department of Fish and Wildlife to
address research problems of interest to the state. Our work primarily
involves training graduate students at the University of Vermont's
Rubenstein's School of Environment and Natural Resources to address key
research needs. It's a great program!
Good news! You can now get pdf files
directly from the Spreadsheet Project website. Each module consists of
instructions for putting together a spreadsheet, a spreadsheet
"shell," that contains column headings, etc. so you can focus your
energy on entering equations rather than headings, a completed spreadsheet,
and answers to questions. If you want one of the original books,
you can buy them on eBay but they cost a lot!
Don't only
sissies use spreadsheets?
Some scientists really hate spreadsheets.
But the truth is that they are a GREAT way to teach students how to think
through ecological or analytical problems. I have taught many courses in
the past few years and started with "canned" educational programs,
where students press buttons, run a simulation, and generate results. I
switched to spreadsheets when I realized that very few students could tell me how
the results were generated or what they mean. I've seen students be
converted from math-phobics to hard-core modelers when they are engaged in
entering equations and developing their own models.
There are many, many options for modeling
ecological processes. If you need to solve equations analytically, you
can use dedicated mathematical program such as MatLab or Mathematica.
Many students like graphically oriented modeling software, such as Stella or
Simile. The graphics in these programs allow students to see how
different pieces of a model are connected to each other.
In general, no. If you have a very small
amount of data to work with, you can probably get away with using a
spreadsheet. However, in most cases you'll want to use a regular
database (like Access or other database program...there are many to choose
from).
No. Excel is fine for simple statistics
like means, totals, etc. But more complicated routines require a
dedicated statistical software package, like SAS, R, SPLUS, etc. If
you must use Excel, check out RExcel.....it uses Excel as a front end
application and R as the stats engine: http://sunsite.univie.ac.at/rcom/server/doc/RExcel.html
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