1. CS&E 1111 ExUnits Effective Workbook Design for Large Problems Objectives: l Efficient/effective worksheet designs l Using multiple worksheets in a workbook l Using Split Screen & Freeze Pane features for large worksheets l Problem solving with “unit” conversions l What-if analyses & Goal Seek

2. CS&E 1111 ExUnits A Problem: Your Gardening Nursery business is growing and you need additional help. You need to determine if you will save money by hiring temporary employees vs. two full time employees. You have the following information: l Temporary employees are paid $10/hour flat rate. You estimate you will need a total of 80 work hours a week for each of the 50 weeks you are open. l Each permanent employee works 40 hours per week and is paid $1000 per month plus benefits worth $5000 per year. Each receives 2 weeks paid vacation while your store is closed in January - so they are paid for a full 12 months. You will need a total of 2 permanent employees.

3. CS&E 1111 ExUnits data inputs calculations output Now Lets Implement This Problem in a Spreadsheet: A Single Worksheet Design Is Best With Limited Quantities Of Data By listing each input separately – it will be easy to make changes without worrying about where each value is used.

4. CS&E 1111 ExUnits Designing a Spreadsheet Solution Using Multiple Worksheets l When creating spreadsheets with large amounts of related data it may be more effective to place each “table” of data in a separate location. l Excel provides us with the ability to have multiple worksheets within one workbook. Sheet tabs Sheets may be named and displayed with different colors tabs, The order of the worksheets may be modified as well.

5. CS&E 1111 ExUnits inputcalc Formulas Syntax:Sheetname!Cell Reference Formulas may include cell references from multiple worksheets: input!B1*input!B3 When referencing a cell on the same spreadsheet as the active cell the sheet name is not required. C2+C3 Named ranges are unique to a workbook. So if cell input!B1 is named ‘employee’ the formula in cell C3 could be written as employee * input!B3 Referencing Cells on Multiple Worksheets

6. CS&E 1111 ExUnits inputcalc The results of both analyses are presented on a single sheet One method of organizing your data is with separate sheets for inputs, calculations and/or outputs. This works well in the following instances: Many different sheets share the same inputs – so each piece of data need only be changed in one location When you want to present the results only on a single sheet comparing each of the different analyses

7. CS&E 1111 ExUnits Excel allows you to view multiple worksheets on your screen 1.If your worksheet is maximized click on the Restore Window button. 2.Then size the window to easily view the contents of the worksheet using the sizing arrow from the edges of the window. 3.Open another window by selecting New Windows from the View Ribbon. 4.Select the next worksheet you desire to view and size it and place it on the screen so the contents is easy to view.

8. CS&E 1111 ExUnits This works well when: Different cases have different input values When you want to present the inputs/outputs and calculations of a single case on one sheet. Another method of organizing workbooks is using separate sheets for different “cases”

9. CS&E 1111 ExUnits One advantage of using separate sheets for different “cases” is the ability to easily create summary sheets We can write a single 3-Dimensional Formula and then copy it down the column & across the row =SUM(case1:case3!B12) or = case1!B12+case2!B12+case3!B12 case1! case2! case3!

10. CS&E 1111 ExUnits Editing Multiple Worksheets Simultaneously By holding down the Shift key we can select multiple worksheets simultaneously. When a [Group] is selected any changes made to a cell will be made to that same cell on all worksheets in that [Group]. To de- select a [Group] click on any worksheet not in the Group. When multiple worksheets are selected the Title bar adds [Group] to the title. Be careful when using groups not to inadvertently change something on another sheet that you didn’t want to.

11. CS&E 1111 ExUnits Problems with Large Data Sets Consider a different example where you are analyzing a large dataset of gas prices.

12. CS&E 1111 ExUnits Split Screen, Freeze Pane and Hide Tools l Split Screen creates sections that can each be independently scrolled. l Freeze Panes lets you freeze column and or row titles

13. CS&E 1111 ExUnits Sometimes its not just the organization of the worksheets – but equating “units” in our problem solution Land development: Acres  Square Feet Drapery fabric: Square Feet  Square Yards Nutrition: Grams of Fat  Calories Foreign Currency Exchange: Dollars  Euros Interest: Annual Percentage Rate  Daily Rate How do we mathematically convert units and how can Excel help us with this task?

14. CS&E 1111 ExUnits Consider another Problem: You are a developer considering two adjacent pieces of property to purchase in order to construct homes on 10,000 SF plots. Which one is more cost effective cost per square foot ? $100,000 for 10 Acres $120,000 for 40 10,000 SF plots OR

15. CS&E 1111 ExUnits What information do you have? l Option 1 l Number of acres l Total dollars l 43,560 SF per acre l Option 2 l Number of plots l SF per plot l Total dollars Costs per SF What information do you need?

16. CS&E 1111 ExUnits Option 1 Analysis Have: Number of acres = 10Total dollars = $100,000 There are 43,560 SF per acre If you are given number of acres, and total dollars and want $/SF what do you do? acres * 43560 SF acre 10 = 435,600 SF The same units in the numerator & the denominator cancel out =.23 $/SF $100,000 ÷ 435,600 SF

17. CS&E 1111 ExUnits If you are given data in dollars and want dollars per square foot ($/SF) what do you do? Option 2 Analysis Have: l Number of plots = 40 l SF per plot = 10,000 l Total dollars = 120,000 = $/Plot 3000 40 plots $120,000 ÷ plot 10,000 SF $3000 plot  When you divide, the denominator of a denominator becomes the numerator or alternatively multiply by 1 over the value plot 10,000 SF $3000 plot = $.30/SF

18. CS&E 1111 ExUnits Now you can add or subtract like units to compare l Option 1 l Number of acres l Total dollars l 43,560 SF per acre l Option 2 l Number of plots l SF per plot l Total dollars.23 $/SF.30 $/SF Option 1 provides land at 7 cents per square foot less than the land in Option 2.30 $/SF -.23 $/SF =.07 $/SF Compare Like Units

19. CS&E 1111 ExUnits data inputs output Select a Single Worksheet Design Implementation By listing each input separately – it will be easy to perform what-if analyses Intermediatecalculations

20. CS&E 1111 ExUnits Another Example: Which car is the best buy after 5 years? l Car A costs $20,000 and gets 20 miles per gallon l Car B costs $25,000 and gets 30 miles per gallon l You can assume you drive an average of 12,000 miles per year and the cost of gas is $4/gallon Total Cost  Purchase price + # years driven * Cost per year of gas

21. CS&E 1111 ExUnits To get cost per year of gas we need to calculate the number of gallons per year? Miles Gallon Year x Multiplying miles/gallon by miles/year results in miles 2 /gallon-year Dividing miles/gallon by miles per year the result is years/gallon Miles Gallon Year ÷ Miles Miles Year Gallon Dividing miles/year by miles per gallon the result is gallons/year ÷

22. CS&E 1111 ExUnits Cancel like units in the numerator & denominator. Miles Year Miles Gallon Gallons Year Units in the denominator of the denominator become the numerator Gallons Year Dollar Gallon Dollars Year x

23. CS&E 1111 ExUnits Now complete the calculation Total Cost  Purchase price + # years driven * Cost per year of gas miles year gallon dollars gallon x ÷ Cost of the car + # years x =B6+C$3*(C$1/C6*C$2)

24. CS&E 1111 ExUnits If you have an effective spreadsheet design – it is easy to create a What-if Analysis Change one or more input values  affected formulas are automatically recalculated By Modifying the miles per year and number of years all cells based on that value are automatically changed.

25. CS&E 1111 ExUnits Goal Seek allows us to determine an Input Value that would be needed to get a Given Output l Allows us to work backwards in a worksheet l Lets you vary only one input variable l What-if analysis in the reverse direction. l Ex. What would the price of gas have to be to such that the total cost of the economy car (purchase + gas) is $30,000?

26. CS&E 1111 ExUnits If we want the value in D6 to be $30000, what would the value in C2 ($/gal) have to be, assuming none of the other inputs change? Goal Seek can be accessed from the Data Ribbon Tools Group

27. CS&E 1111 ExUnits Design Your Worksheet: A simple example with very few options The calculations for each option are different Want to compare inputs as well as final output Use a single worksheet design A more complex example Inputs are shared between options and do not vary independently Input may contain large datasets Inputs with complex calculations Want to compare outputs only Separate inputs & outputs onto different worksheets A more complex example with multiple options Calculations for each option are the same but input values vary Want to compare inputs as well as final output Place inputs/outputs for each case on a single worksheet in an identical design, then use a summary worksheet

28. CS&E 1111 ExUnits Some tips for designing your workbooks l Think before “typing” –organize your data, determine which inputs are likely to vary and which are fixed. l Unless you have a very simple problem - consider multiple worksheets for multi-table input/outputs or multiple cases. l Each data input should appear once and be used as a reference in subsequent calculations. Make sure you have correctly identified unit conversions and incorporated them into your solution l Document your workbooks - so that they can be easily understood by others