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  1. 1. SSAChaz.TCJ.1 Risk assessment for Benton County, Oregon, Part I: Using Excel for the first time Benton County, Oregon, faces many hazards related to earthquakes. How can Excel help to quantify them? The module you are viewing is a PowerPoint slide presentation. Core Quantitative Literacy Topics •Navigate from slide to slide using the up/down arrow keys, or the scroll wheel on the Function mouse if one is available •Use the mouse to select hyperlinks (underlined, in blue type) Supporting Quantitative Literacy Topics •When done, use the escape key to exit the presentation. Order of operations You can and probably should have a spreadsheet open in a separate window, so you can try out things that are explained in the presentation. Core Geoscience Subject PowerPoint applications use lots of memory, so you may want to exit other programs Risk assessment while running this presentation, especially if it starts to act slowly or sluggishly. If you don’t immediately see the slideshow when switching back and forth between windows, use the up/down arrow keys (or scroll wheel on mouse) to ‘wake it up’. Thomas Juster , Dorien McGee, Meghan Lindsey, and Len Vacher Department of Geology, University of South Florida © Close this window to proceed Libraries. All rights reserved, 2010, 2011 University of South Florida with the slide show. 1
  2. 2. How this worksThis PowerPoint presentation provides the instructions for an auto-grading Excel spreadsheetrequiring you to complete several tasks. The spreadsheet is a separate companion file youshould open and complete while you are viewing this slideshow. When you’ve successfullyfinished the spreadsheet you’ll be given a secret code that contains your name and score,which you’ll submit to your instructor to receive a grade.The companion spreadsheet file is an Excel 2007/2010 macro-enabled spreadsheet file. Thefile may or may not work with earlier versions of Excel (e.g., 2003)—so use these at your ownrisk. Note that you must agree to enable macros in order to run the spreadsheet (you will beprompted when you first try to run it). If you do not agree to run macros, or your computer forsome reason prevents them from running, you will not be able to complete this activity. Thespreadsheet file will not work on Apple computers or iPads.In order to receive any credit for this activity you must complete the preliminary tasks in order,must complete each one perfectly, and must complete all of them. The spreadsheet helps yousucceed by giving feedback on wrong answers. Once you have completed the preliminary tasksyou will be presented with one final task and given the opportunity to submit your grade to thecode generator. You can submit your grade at any time during the final task, but of course you’llprobably want to wait until you’ve completed it perfectly and earned 100%. 2
  3. 3. Getting started After completing this module you should be able to: Benton County •Open, manipulate, and save an Excel file •Know how to use cell addresses in Excel •Understand the difference between text, numbers, and formulas in Excel cells •Use some simple Excel functions. You should also know where Oregon is! 3
  4. 4. Overview: why use spreadsheets?Geology, like other sciences, is a quantitative subject requiring some quantitative literacy.Numbers are necessary to express sizes, distances, lengths of times, rates of processes, andmany other quantities. To learn geology, you must work with numbers. To some extent, youmust think with numbers. In your Hazards of the Earth’s Surface course, some of your workingand thinking with numbers will be done with spreadsheets.Spreadsheets provide a convenient way to organize numbers and perform elementarycalculations. You many not have had an opportunity to use and make spreadsheets before, orthe time to learn how, so we are providing this module as a tutorial to introduce some of thebasic Excel skills for the spreadsheet activities that will be used in this course.Once you get the hang of spreadsheets, and how to calculate with them, you will find yourselfusing spreadsheets as your calculator of choice in other activities for this course, in otherscourses, and outside the University. 4
  5. 5. How the spreadsheet modules workEach of the spreadsheet modules you will do in this class has the same look and feel as thisone. This consistency will help you know exactly what to do.Blue boxes contain the content of the module. They give you the relevant background andexplain how to perform tasks.Supplementary, often important material will be shown in a red box like this one. Pay attention,because the red boxes often contain important Excel tips that will make your job easier.Actual instructions are given in green boxes, like this one. When you see a green box you knowyou will have to do something that is part of your assignment.All PowerPoint module files, like this one, have a companion Excel spreadsheet file where youwill do calculations. So here’s your first preliminary task: open the companion spreadsheet fileso you can work on it while you view this slideshow. The slideshow and spreadsheet aredesigned to be viewed simultaneously.Your second preliminary task: save the spreadsheet file you just opened under a unique name(e.g., “Joe_Smith-Unit-1”) so you have a record of it. Remember, you will have to agree to allowmacros.This module includes three tasks. The first two are required, and you must do them in order,and complete them perfectly, in order to get access to the last one. So let’s get started! 5
  6. 6. The setting – Benton County, OregonBenton County is located in western Oregon, close to a large earthquake-generating area called theCascadia Subduction Zone. This zone is capable of producing gigantic earthquakes (perhaps akin tothe 2004 Sumatra earthquake that produced the tsunami that killed 220,000 people), and poses thegreatest risk to Benton County. Large earthquakes pose several kinds of risks:•They can topple buildings directly;•They can induce landslides;•They can literally turn sediment into quicksand, causing overlying structures to collapse From the USGSAll photos from the Oregon State archives website 6
  7. 7. Geology of Benton CountyBenton Countycontains many differentrocks and sediment.This is importantbecause, as you willlearn later, earthquakewaves can be amplifiedwhen they passthrough certain kinds ofsediments, and cansometimes eveninduce ‘liquefaction’—the process of turningsediment intoquicksand!On a geologic map, differentkinds of rocks and sedimentsare noted with different colors.The important thing to note onthis map is the distribution ofsediment (as opposed to hardrock), which is called variously“alluvium” or “deposits”. 7
  8. 8. Topography of Benton County As seen in this Google Earth view, the western part of Benton County is rugged and largely unpopulated, while the lower, flatter eastern part contains most of the development. Topography matters because steeper slopes are more prone to landslides. 8
  9. 9. Statement of the ProblemBenton County lies near the Cascadia Subduction Zone, which produces frequent earthquakes,and is capable of producing giant earthquakes. Benton County officials make decisions that areaffected by this risk—for example, they create zoning laws which restrict activities in certainlocations. Your task: calculate the annual risk produced by a giant earthquake (magnitude M ≈ 9.0) for Benton County in terms of both (a) fatalities; and (b) monetary losses, in dollars.This is the first of two modules that will calculate the risk. This module will introduce you to Excel andexplain some of the tools you’ll use to do calculations. In the next module you’ll actually compute therisk. 9
  10. 10. An introduction to Excel: spreadsheet componentsWhen you first open Excel, you are presented with a grid of boxes. This is the spreadsheet onwhich you will enter data. The file itself is called a workbook and is composed of severalspreadsheets which can be accessed by clicking on the tabs at the bottom of the spreadsheet.You may add, delete, or change the name of tabs by right-clicking on the tabs themselves.Above the spreadsheet is the toolbar, and above and below the spreadsheet is a series ofcommand and formatting buttons. Many of these are identical to those used in Microsoft Word.Taking time to familiarize yourself with these first will make using them much easier later. Toolbar and buttons Spreadsheet tabs 10
  11. 11. Spreadsheet components, con’t.Each box in the spreadsheet is called a cell, and each cell has its own unique alphanumeric cellreference. The cell reference begins with a letter, indicating the column in which the cell is found.The cell reference ends with a number, indicating its row. When you select a cell by clicking on it, thecolumn and row to which it belongs will automatically be highlighted, making it easier to identify itscell reference. A field at the bottom-left of the toolbar also indicates the cell reference.Cells are discrete units that can be loaded with text, numbers, or formulas. This tutorial will show youthe various ways cells can be used. Cell reference (A1) Cell 11
  12. 12. Spreadsheet components, con’t.Another key component of the spreadsheet is the function bar. Here is where you can enter a label(text), number, or cell formula (cell equation) into the highlighted cell (click on the cell to highlight it;the address of the cell is in the box to the left of the function bar). You may also type the label,number, or cell formula into the cell itself by selecting it and typing in what you want. If you enter acell formula into a cell and it is correctly formatted, what you type will disappear and be replaced withthe formula’s solution (a number); if it is not correctly formatted, the cell will show an error message.In either case, click on the cell and you can view the cell formula in the function bar. Function bar 12
  13. 13. Spreadsheet components, con’t. Cell formula Solution to cell formula 13
  14. 14. An introduction to Excel: formulasEntering a label or a number is straightforward. Simplytype what you want. What you type is what you get.Entering a formula is only slightly more complicated.The Big Thing is to remember to start with the equalssymbol (=). Again, what you type is what you get. Ifyou type and enter =(2*6)+3Excel will tell you what you get when you multiply 2times 6 and then add 3, which is what the operationsymbols in the formula say. In these activities, we will always use orange to indicateBut if you omit the equals symbol, Excel will think you a cell with a formula.mean text and display (2*6)+3. Excel uses the five standard numberIn our example of =(2*6)+3, the parentheses are operations. Using the numbers 6 and 2, whatunnecessary because multiplication takes precedence numbers should be produced for each of theover addition (Excel multiplies before it adds). Go to following five cell formulas?any blank cell and enter =2*6+3 without the parenthesesand check that you get the same result. For addition, =6+2 For subtraction, =6-2Sometimes the parentheses are very necessary. What For multiplication, =6*2do you get when you type the following? For division, =6/2 =2+6*3 For exponentiation, =6^2 =(2+6)*3 Check your answers with ExcelExcel uses the rules for order of operations. 14
  15. 15. Task #1: Using formulas in ExcelYour first task is to complete the table onrows 5 – 13 of your spreadsheet. Thistable summarizes the distribution of In thesestructures in Benton County based on activities, wetheir use. Your ultimate goal is to compute will alwaysthe percentage of each class of structure, use yellow to indicate a cellbut to do this you’ll first need to compute with athe sum of all structures into Cell C13. number.You can find the sum by typing in aformula that adds the numbers and places We will always use orange to indicate a cell with a formula.the result in cell C13 (look in the function These should always start withbar). =But why do it that way? Use cell addresses insteadof numbers! What do you get when you enter : The lesson? You should always use = C6 + C7 + C8 + C9 + C10 + C11 + C12 cell addresses in formulas when youinto Cell C13 or the function bar? can! That way, if you make a change in one number you don’t have toOops! Suppose we miscounted schools. . . there are change the formula. (Now go andactually 200. What happens to the total if we just change 200 back to 198!)change 198 to 200? 15
  16. 16. Task #1, con’t.It is an immense convenience to use cell addresses. Let’s take another example. Look whathappens when we use them to calculate the percentage of each type of structure. This column has already been created for you on your embedded spreadsheet, and labeled %. Note that Cell D6 is highlighted. The number shown in the cell is the percentage of buildings that are happened?!? got that number by Yikes! What residential. We typing inWhy formula shownhave function bar, =C6/C13. the do all the cells in the errors (Excel’s way of telling We could now go and error in to use you there’s an type is formulas for all the other cells in column C; e.g., =C7/C13 for cell D7, etc. But in Excel the # symbol) there’s an easier way: we can copy the formula!There are a couple of ways to copy a formula. Here is one of them: Select the cell containingthe formula you wish to copy. Click the small black box in the lower-right corner of thehighlighted cell (your cursor should turn into a thin black cross when you’ve in the right spot)….…. and drag down until the box extends to the desired row. When you release the mousebutton, your formula will be copied into the selected cells.To understand what went wrong, highlight any of the cells with errors and study the formula inthe function bar. What’s wrong with the formula? 16
  17. 17. Task #1, con’t. The solution in Excel is to use an absolute cell address, which is indicated by dollar signs ($) before the column and row identifier; e.g., $C$13This error highlights one of the key properties of Excel cellreferences: by default they’re relative.For example, you may have thought that the formula =C6/C13 meant, “divide the contents of cell C6 by the contentsof C13 . . . But that’s wrong! What it actually means is,“Divide the contents of the cell one column overby the contents of the cell one column over and sevenrows down, and then put the result intothis cell” Repair yourformula inin Cell D6 Check the formula thisBut that’s not what you wanted! When you wrote C13 you cell. Doesn’t it instruct then copy it down to cells D7meant C13—always C13! In fact, what you wanted to tell throughto do exactly what’s Excel D12. Is it better now?Excel to do is: written on the left? See Endnote 1 for other ways to“Divide the contents of the cell one column over by the copy and paste.contents of cell C13, and put the result here” 17
  18. 18. Task #1, con’t. Then click on one of the format styles. In this case we click on ’%’ To change the formatting of a block of cells, first select them using the mouse You can adjust the number of decimal places by clicking on either of these butonsYou may have been wondering how Excel knew to express the contents of column D aspercents. After all, we just told it to divide whatever’s in column C by the contents in C13, whichcould have been expressed as a fraction; i.e., 0.91.In Excel, percentage is a formatting option. (You should know that percentage is a fraction, withdenominator equal to 100.) 18
  19. 19. Task #1, con’t.A function is one of the most important concepts inquantitative literacy. The quantitative literacy bookUnderstanding our Quantitative World 1 starts withfunctions in its chapter 1. That book defines a function asa “rule” that, for each valid input, assigns one and onlyone output.In math classes, you have probably seen functions writtenin terms of x’s and y’s. For example, consider y = x / 20992Here, x is the input variable, and y is the output variable. Now consider what’s written inYou obtain a value of y by dividing the value of x by the function bar. Instead of20992. That’s the rule that defines this function. writing y and x for the output and input variables, Excel writesMore succinctly, you can say y is a function of x, which C6 and C13, respectively. Theyou can write as y = f(x). The rule for this example then is rule connecting them isgiven by C6 = B6/20992 f(x) = x / 20992. Or, since 20992 represents theJanet Anderson and Todd Swanson, 2005, Mathematics Association of America.1 contents of cell C13, we can write the function as C6 = C6/$C$13 19
  20. 20. Task #1, con’t.Your formula is a function!In addition to functions that you can create such as f(x)= C3/C13, you can use many functions that Excel hasbuilt in. One of these is the function that totals a rangeof numbers.In Excel, a range of numbers is indicated with a colon(:) between two cell references. For example, the rangeof numbers that represents the number of structures ofdifferent type is C6:C12 (outlined in red).The function that calculates the sum of numbers in arange is called—unsurprisingly—the SUM function. Forexample, we could have used the SUM function in cell This is how you use the SUMC13 instead of having to enter all the numbers above function: =SUM(C6:C12).into a long formula. You should always use the sumfunction when you’re adding more than 2 or 3 numbers. Use the SUM function to check that the percents you calculated in column D sum to 100%. 20
  21. 21. How the auto-graded spreadsheets workA key feature of these modules is that they are automatically graded; you will earn points bydoing things correctly, and only then will the next problem be revealed. The program is alsodesigned to give you help and hints if needed, and of course you are also encouraged toconsult with your TA or instructor if you’re lost. Here’s the first task, partially completed. Oops! It’s not quite right. At any time you can check to see how well Napoleon forgot to fill in Cell D13 you’ve done by clicking on the blue button. and cells D6-D12 lack absolute cell references. Remember them? (See Slide 17). This example makes an important point: not only do you have to get all your numbers correct, but you have to get them correct in the correct way! So what’s in the cell equation is as important as the result. Pressing <ctrl>-a will bring up a short help screen which hopefully will tell you how to fix the mistake. 21
  22. 22. How the auto-graded spreadsheets work, con’t.When you’ve completed Task #1 perfectly, pushing the Blue Buttonwill bring happy news . . . first a congratulatory message box: 40 . . . and then 40 well-earned points, plus the opportunity to start on Task #2, which has been revealed in rows 15-18 22
  23. 23. Task #2, More about built-in functionsThe next two slides will explain more about functions,which you need to use to complete Task #2.Numerous other functions apply to fields of data. Thisspreadsheet (which is not yours) shows four of them: =AVERAGE(B3:B9) =MAX(B3:B9) =MIN(B3:B9) =COUNT(B3:B9) You can also write formulas that do arithmetic with built-in functions. For example, can you recognize what other function this formula mimics? If you’re not sure how to =SUM(B3:B9)/COUNT(B3:B9) use a function, select the cell with the function and then click on the Function . . . and a window will appear telling you what the function button (fx) to the left of the does and what kind of arguments it takes. function bar . . . 23
  24. 24. Task #2, con’t. 5If you just want to explore the various functionsavailable, click on the Function button (fx) whileselecting a blank cell . . . Click to select blank cell, then click fx … and a window will appear that allows What does the function PRODUCT() do? you to search for a function, select Hint: this is a ‘Math & Trig” function; you functions from a category, and shows you need to choose this category how you how to format its formula. 24
  25. 25. Task #2, con’t.So here’s what you have to do for Task #2: enter thecorrect formulas into cells C15-C18 to compute theaverage, maximum, minimum, and count of thebuilding classes in cells C6-C12. If you understoodthe last few slides this should be very easy!Once again, click on the Blue Button to check yourwork. If you’ve done it all correctly you’ll earn another20 points and move onto Task 3, the final task. 25
  26. 26. Final TaskThe final task is a little different than the preliminary tasks.•First, you don’t have to do it, though this will obviously hurt your final score.•Second, partial credit is awarded, and reflected in the Total Score box. So every time you clickon the Blue Box to check your work your score is reevaluated and displayed. Just like always,the spreadsheet will give you feedback on incorrect answers, and you can (and should!) keeptinkering with your spreadsheet until it is perfect.If you do final task perfectly, you’re done—the program will calculate your secret code anddisplay it for you. The maximum score on the spreadsheets is 100. Clicking the Blue Box will If you’re satisfied with your score, even though it’s not 100, check your answers, just just click on the red box to end the module and get your code. like for the other Tasks. But note that you can only choose this option once—once you’re done, you will no longer be able to improve your score. 60 When you finish Task #2 correctly, this final task will be revealed. Hopefully you can immediately see how to do it, since it simply requires you to apply what you’ve learned on the previous tasks. 26
  27. 27. Final TaskFor example, here’s what Napoleon sees after he bailed with 60 points.Once you’ve obtained your code, This is his secret code, which he will need to supply towrite it down or, better yet, create a Blackboard when he takes the quiz for this module.screen-shot of this page and save it The code contains his score (60/100) along with aon your computer. You will need your bunch of other encrypted information that yourcode to get credit for your instructor will decode to conclude, with a sigh, thatspreadsheet work. Napoleon really didn’t put much effort into Module 1. 27
  28. 28. Final TaskThe structures in Benton County can also be classified on the basis of their construction, asshown in the table below: Type Count Wood 17,050 Steel 457 Concrete 291 Precast concrete 266 Reinforced masonry 389 Unreinforced masonry 290 Mobile homes 2,249Complete the spreadsheet table that computes the total number of structures, and thepercentage for each construction. Your table should look very similar to the one on Slide 22. 28
  29. 29. Endnotes1. Excel gives you myriad ways to copy and paste. Most people find one they like, and remember, and use it all the time. Here’s another way to do it. a. Select the cell you want to copy (position the cursor on it and click); b. Then right-click and select ‘Copy’; c. Now position the cursor where you want to copy (which might include selecting a range of cells); and d. Right-click and select ‘Paste’ Go back to Slide 17. 29