MS Office for Engineers

MS Office for Engineers Lesson 4 Excel 2 Pre-reqs/Technical Skills Basic knowledge of Excel Completion of Excel 1 tutorial Basic computer use Expectations Read lesson material Implement steps in software while reading through lesson material Complete quiz on Blackboard Submit completed assignment on Blackboard Ask questions as needed Objectives/Measurables Learn the basics of using MS Excel to create formatted engineering spreadsheets, measured via score on assignment Learn various features in MS Excel, measured via Blackboard quiz score Lecture Topics Cell References and Common Functions Dragging Cells Simple Logic Statements Number Formatting Format Painting Conditional Formatting Table of Contents MS Office for Engineers... 1 Lesson 4 Excel 2... 1 Pre-reqs/Technical Skills... 1 Expectations... 1 Objectives/Measurables... 1 Lecture Topics... 1 Introduction - Microsoft Excel 2010... 2 Cell References... 2 Common Functions... 3 Dragging Cells... 4 Simple Logic Statements... 4 Number Formatting... 5 Format Painting... 7 Conditional Formatting... 7 Worksheets... 8 Charting... 9 Bar and Column Charts... 10 Stacked Column Charts... 15 Assignment... 17 1

Introduction - Microsoft Excel 2010 Microsoft Excel is a commonly used spreadsheet program. It is used by engineers for creating tables for use in technical documents as well as for data manipulation, charting data and simple mathematical modeling. This tutorial will focus on using Excel to create engineering spreadsheets. The specific version of Excel covered in this tutorial is 2010. Earlier versions may not be compatible with this tutorial due to the use of the Ribbon user interface. This tutorial provides basic information on a few topics related to creating technical documents in Excel, for more help consult Microsoft s Help database (the blue question mark at the upper-right corner of Excel as shown in Figure 1. Figure 1 - Excel Help Cell References Often when developing formulas in engineering spreadsheets, it is useful to make an absolute reference to a specific cell, column or row. Such references will not change if the contents of the cell containing the formula are moved or copied to another cell. If you reference a cell in a formula by clicking on the cell while editing the formula, a relative reference is used for both the column and row of the cell clicked. This means that if the content of the cell containing the formula is moved to another cell, the reference in the formula will change to match the number of columns and rows moved from the origin cell to the destination cell. For example, see Figure 2. In this figure, four cells have values (A1, A2, B1 and B2). If you want to reference A1 in a formula, you could click on cell A1 while typing in the formula or type the reference A1 in the formula manually (see cell A4 in the figure). If you copy and paste the contents of the cell containing the formula into adjacent cells, the reference changes. In Figure 2, the content of A4 has been pasted into cells A5, B4 and B5 (another method of moving the contents of a cell to adjacent cells is to simply drag the handle at the lower-right corner of a selection of cells). Figure 2 - Relative References To prevent the column reference from changing as a formula is moved to a different cell, you can add an absolute column reference. This is simply done by adding a $ before the column reference. See Figure 3 for an example. In this figure, the column reference does not change as the content of the cell containing the formula with the reference is moved. The same can be done with row by adding a $ before the row reference (Figure 4). Row and column references can both be made into absolute references by adding $ before the row and column in a formula (Figure 5). 2

Figure 3 - Absolute Column Reference Figure 4 - Absolute Row Reference Figure 5 - Absolute Row and Column Reference Common Functions Absolute row and column references appear often in engineering spreadsheets along with several frequently used functions. Some of these common functions are listed in Table 1 Table 1- Common functions Function =AVERAGE(cells) =MAX(cells) =LARGE(cells, k) =MIN(cells) =SMALL(cells, k) =ABS(cells) =STDEV(cells) =COUNTIF(cells, value) =PI() =EXP(cell or value) =LOG(cell or value) =LOG10(cell or value) Description Mean (average) Largest k-th largest value Smallest k-th smallest value Absolute value Sample standard deviation Number of cells containing the value The value of π e raised to value of the cell (or just value) Natural logarithm of value of the cell (or just value) Base-10 logarithm of value of the cell (or just value) 3

Note that Excel formulas operate on the values in cells (i.e. numbers) not symbolic variables. If need to use a program to solve equations symbolically (e.g. solve 34+x=40 for x) you will have to use a symbolic manipulation program such as Mathematica or Maple. Both are available on the Missouri S&T campus. Modern calculators have limited symbolic manipulation capability as well. Dragging Cells To duplicate the content of a cell to adjacent cells, you can left-click drag the cell handle that appears at the bottom-right corner (Figure 6) of a selected cell (or group of cells). Dragging the handle to adjacent cells will extend the content of the previously selected cell(s) into the newly selected cell(s). This includes formulas and formatting. References in formulas will be adjusted if not made absolute (if you drag the contents of a cell from Column A to Column B a reference to Cell A1 will change to Cell B1. Copying and pasting cells defaults to this behavior as well (references are updated). Figure 6 - Cell Handle Dragging If you left-click drag a cell (or selection of cells) by the border (Figure 7), not the handle, it will simply move the contents to the new location without changing formula references in the cell (reference to that cell, or group of cells, will however adjust to the new location). This is useful if you need to relocate a cell (or group of cells) without breaking formula references. Figure 7 - Cell Border Dragging Simple Logic Statements In addition to formulas, logic statements can be used in cells. The most commonly used logic statement is =IF(logic_test,if_true,if_false). This statement allows you to create a logic test that references a cell (or group of cells) and produce different results if the statement is true or false. These statements can be nested (up to a limit of 64). This is useful in many engineering spreadsheets. Most notably, a grade assignment can be used with nested =IF() statements (Figure 8). A logic test compares two arguments, a left side and a right side, based on the logic operator. Logic operators include = for equal to, < for less than, > for greater than, <= for less than or equal to, >= for greater than or equal to and finally <> for not equal to. Figure 8 - Grading Using Logic Statements 4

Be careful when using operators with an equal sign in them (=,<=, etc.) on real numbers. For integers, equal operators can be checked simply (2=2, etc.). For real numbers, this presents a problem on computers with finite precision calculations (does 0.749 = 0.750, etc.). When using logic operators on real numbers, it is better to use less than or greater than statements for all logic operations. To compare two real numbers to see if they are equal, it is better to use a statement like the one in Figure 9 than a simple equal (=) statement. This lets you set the precision rather than leave it to the computer. Figure 9 - Equal Statement for Real Numbers Number Formatting Excel allows you to display the content of a cell differently from the actual value contained in the cell. For example, when performing calculations on real numbers, Excel will use at most 15 significant figures in calculations. Any significant figures outside of 15 will be lost (they aren t even calculated or stored). This type of error is called representation or truncation error. In many applications, the last significant digit in a real number calculation is not rounded (it is simple truncated). This error is unavoidable in digital computers and must be fundamentally understood and managed by engineers who wish to use computers (and calculators) to perform calculations. Even though Excel uses 15 significant figures when calculating values, you might not want to see them all at the same time (even though you want Excel to keep them around for future calculations). Excel allows you to choose the display value of a cell independently from its actual value for this reason. To change the displayed number formatting options for a cell (or group of cells) right click the cell (or group) and select Format Cells to open the Format Cells dialog (Figure 10). Figure 10 - Formatting Cells 5

Figure 11 - Format Cells Dialog (Number) The Number tab (Figure 11) in the Format Cells dialog allows you to select the display format of the selected cell(s). It defaults to General. If the format is set to General, Excel uses the content of the cell(s) to pick a display format. If the General format option does not provide the result you want, you can select from the Category list. For real numbers, select Number and set the number of decimal places (Figure 12). You can also change the way negative numbers are represented (some accounting spreadsheets use red for negative numbers). Figure 12 - Number Options 6

Currency ($, etc.) formats can be used along with dates, times, percentages and scientific numbers. Note that changing the format does not change the actual value in a cell. Reducing the number of decimal places displayed does not remove significant figures from a cell. Format Painting Like copying and pasting the values of cells from one place to another, the formatting of cells can be pasted to other cells. By default, when you copy and paste a cell, its value (and formatting) is added to the new cell. If you just want the formatting to be added, use the Format Painter. If works similarly to copying and pasting. To use the Format Painter, select the cell(s) with the formatting you would like to copy (Figure 13). Click the Format Painter button in the Clipboard pane of the Home tab. The cursor icon will change to the Format Painter icon (with a little paint brush). You can now select a cell (or group of cells by left-click dragging) to paste the format from the original selection without changing the destination cell(s) values (Figure 14). Figure 13 - Format Painter (Before) Figure 14 - Format Painter (After) Conditional Formatting Excel provides a convenient method for allowing the formatting of a cell to adapt based on its value. This feature is called Conditional Formatting and is useful in engineering spreadsheets. Most Conditional Formatting options allow the background color of a cell to change based on the value in the cell. Alternatively, icons or percentage bars can be added as well. This provides a visual method of differentiating cells without directly comparing values or using logic statements. Examples are shown in Figure 15. Figure 15 - Conditional Formatting In the examples shown in the figure, the cell is formatted based on the relative value of the cells in the conditional formatting group. In the left column, the highest number is shaded green, the lowest red and numbers in-between are shaded between green and red proportionally. Percent bars are used in the second 7

column. Icons are used in the third. Finally, a grading logic statement is used in the fourth column. To apply Conditional Formatting, select the data you want to format and select the Conditional Formatting button in the Styles pane of the Home tab. This opens the pop-up shown in Figure 16. From this pop up, simple rules can be constructed using logic statements (Highlight Cells rules), the formatting shown in Figure #### can be used with the Data Bars, Color Scales or Icon Sets or custom rules can be established in detail using the New Rule option. Rules can be cleared with the Clear Rules selection. Figure 16 - Conditional Formatting Rules Worksheets When you first open a new Excel spreadsheet, three worksheets are included by default. These sheets appear as tabs at the bottom of the user interface (Figure 17). Figure 17 - Worksheet Tabs You can change sheets by clicking on the label for the sheet you want to select. The sheet order can be changed by left-click dragging a sheet label to a new spot in the sheet order. An arrow will appear to show where the sheet will be moved (Figure 18). 8

Figure 18 - Moving a Worksheet A new sheet can be added by clicking the New Sheet tab (Figure 19). The new sheet will be added to end of the sheet order. Figure 19 - New Sheet Tab Sheets can be inserted, deleted, moved, copied and hidden with the sheet popup (Figure 20). To open this popup, right-click on a sheet tab. Figure 20 - Worksheet Pop-up The cells contained in a worksheet can be referenced by other worksheets in the same spreadsheet. When entering a formula, you can change worksheets by clicking the relevant worksheet tab and then select a cell (or group of cells) in the newly opened worksheet. Alternatively, you can reference the worksheet by name using the following format: [worksheet_name]![column_letter][row_number]. For example, if you wanted to reference cell A8 in a worksheet named Data you would use Data!A8 in the formula. Charting In additional to representing data in tables, Excel lets you create charts based on data sets. Excel has numerous chart types built in (Figure 21). 9

Figure 21 - Chart Types Bar and Column Charts Bar and column charts are often used in engineering spreadsheets. For example, if you wanted to visualize the relative magnitude of the criterion weights in a decision matrix (Figure 22), you could create a simple bar or column chart. Figure 22 - Decision Matrix There are two approaches to creating charts, the first is to insert an empty chart and then select data manually. Alternatively, the data can be selected and then a chart added based on the data selection. The latter method will be covered here. To create a simple column chart for the weighted importance scores in the decision matrix 10

shown in Figure 22, select the cells highlighted in red. Click the Column button in the Charts pane of the Insert tab. For the resulting pop-up, select Clustered Column from the 2-D Column row. The chart shown in Figure 23 results. Figure 23 - Sample Chart Note that no labels or titles are included. Charts used in technical documents and presentations must include both titles and axis labels for clarity. To add labels to the bars, open the Select Data dialog (Figure 24) by leftclicking within the boundary of the chart (to select it) then right-clicking to open the chart pop-up. In this popup click the Select Data option. Figure 24 - Select Data Dialog In this dialog, the labels for each bar can be changed. By default, labels are numbered in order. To change the labels to match those in the worksheet, click the Edit button in the Horizontal (Category) Axis Labels group. A dialog opens that will allow you to select the cells containing the labels. Left-click drag over the cells containing the labels in the spreadsheet or manually type in the list. See Figure 25 for an example. Once you hit OK, the labels will be updated. 11

Figure 25 - Selecting Labels While you are in the Select Data Source dialog, the Series label can be changed as well (Series1 in the example). To change this, click the Edit button in the Legend Entries (Series) group. The dialog shown in Figure 26 appears. In this dialog enter a name in the Series Name box (a cell containing the name can be used as well). Figure 26 - Changing the Series Name Once a name is entered, clicking OK on the Edit Series dialog and Select Data source dialog will update the chart (Figure 27). 12

Figure 27 - Updated Chart Since this chart contains only one series, the legend can be removed. To delete the legend, click once on the chart to select it, then click again on the legend title to select it specifically. Press the Delete key on the keyboard (or right-click and select Delete from the pop-up). The legend will be deleted and the chart area resized to fill the chart boundary (Figure 28). Figure 28 - Legend Deleted The last items to added to the chart are axis labels. To add labels, select the chart (left-click within the boundary), then go to the Layout under Chart Tools (Figure 29). 13

Figure 29 - Chart Layout Tools To add a label to the horizontal axis, click the Axis Titles button in the Labels pane, then select Title Below Axis under the Primary Horizontal Axis Title option (Figure 30). This will add a text box to the chart with placeholder text. Figure 30 - Adding Axis Titles The text can then be changed by selecting the text box with a left-click and then typing in the correct title. This can be done for the vertical axis by selecting a title type from the Primary Vertical Axis Title option (shown in Figure 30 as well). See Figure 31 for a table with both axis titles added. Figure 31 - Completed Chart 14

The chart is now complete and can be pasted into a presentation or document using Office s copy and paste. If you would like the chart to appear in a worksheet separate from the sheet containing the data, right-click on the chart and select the Move Chart option (Figure 32). In the Move Chart dialog (Figure 33), select the New Sheet radio button then enter a name in the New Sheet text box. Click OK and the chart will be moved to a new worksheet. Figure 32 - Moving a Chart Figure 33 - Adding a New Sheet for the Chart Stacked Column Charts Stacked column charts can be used to show how various data entries contribute to a total value. For each concept, a stacked bar can show the total concept score along with how individual criterion score contribute to this total. To create a stacked column chart showing this information for the decision matrix, select the weighted criterion scores for all concepts (left-click drag the scores for the first concept, the hold Ctrl on the keyboard and left-click drag the columns for each of the other concepts). See Figure 34 for the columns to select. Figure 34 - Data to Select 15

Once the data is selected, insert a Stacked Column chart. Use the same process as the Clustered Column, just select Stacked Column instead. The chart shown in Figure 35 appears. Note that this chart isn't exactly what we need. Each bar shows how each concept contributes to a specific criterion. We need the opposite. To get this, select the chart, right-click and open the Select Data dialog. In this dialog, click the Switch Row/Column button (Figure 36). Figure 35 - Chart Added (Rows/Columns Switched) Figure 36 - Swapping Rows/Columns The rows and columns are now swapped and the chart should be formatted as needed. Before closing the Data Source dialog, change the series names and axis labels to something more appropriate Figure 37. Figure 37 - Chart Fixed 16

Assignment Your assignment is to create a decision matrix using Excel. A decision matrix is a table that contains concepts and criteria. For each criterion, a raw importance is assigned between 1 and 5. An importance of 1 means that the criterion is not very important to the success of the design while an importance of 5 means that criterion is of critical importance. These values are summed and then this sum is used to divide each criterion importance into a weighted importance. Each concept is then assigned a value of 1-5 for each criteria. A value of 1 means that concept does a very poor job of satisfying that criterion while a value of 5 means it does an excellent job satisfying the criterion. This value is then multiplied by the weighted importance for the criterion to produce a criterion score, these scores are then summed to produce a concept score and divided by 5 (the maximum score). The concept score is then used to sort concepts from best to worst. Your decision matrix must include the following content: Placeholders for four concepts (1 pt) Placeholders for four criteria (1 pt) Formulas for calculating weighted importances, weighted criterion scores and concept scores (3 pts) Borders and shading (1 pt) Conditional formatting on criterion and/or concept scores (2 pts) Cells using MAX, MIN and AVERAGE equations for concept scores (3 pts) See Figure 38 for an example. 17

Figure 38 - Decision Matrix Example As seen in Figure 38, Cell B12 is the sum of cells B6-B11. Cells C6-C11 are the values in B6-B11 each divided by the total in B12. The weighted concept scores in columns E, G I and K are the raw scores in columns D, F, H and J each multiplied by the weighted importance in column C. The totals in E12, G12, I12, and K12 are the sums of the weighted concept scores for each concept divided by the maximum score value (5 in this case). The result is a number between 0 and 1 (essentially a percentage) that indicates the relative value of each concept. The best, worst and average score cells (B14-B16 respectively) are taken from the numbers in E12, G12, I12 and K12. Create two charts for the decision matrix. One chart should show how the weighted importance scores contribute to the total importance (something like Figure 31 or a pie chart like in Figure 39). The other chart should show a comparison of concept scores for each concept with the contribution of each criterion to each concept visible (like Figure 37). Use fabricated data, or data from your team (this is an individual assignment, and it is a trivial task to see if an excel file was copied directly from a teammate). Each chart should be a separate worksheet from the data worksheet. Delete all other worksheets (the spreadsheet should only contain the data sheet and two chart sheets). Scoring will be as follows: Importance chart (2 pts) Concept chart (2 pts) A lack of professionalism will result in a score of zero points, this includes: A large number of spelling/grammar errors Obscene or inappropriate content, if you have to ask the answer is no Plagiarism of text (images should be public-domain or properly cited) Importances 11% 28% 17% 16% 28% Safety Weight Efficiency Cost Simplicity Figure 39 - Pie Chart 18