EDIT202 Spreadsheet Lab Prep Sheet

Transcription

1 EDIT202 Spreadsheet Lab Prep Sheet While it is clear to see how a spreadsheet may be used in a classroom to aid a teacher in marking (as your lab will clearly indicate), it should be noted that spreadsheets can be used for far more than just marking. The use of spreadsheets can be incorporated for use in almost all subject areas and grade levels whether it is to perform simple mathematical operations or managing complex statistics. Some key concepts that will be covered in this prep sheet include: - Formatting the data in a spreadsheet - How to use formulas and functions - Managing multiple sheets - Sorting and protecting the data in a spreadsheet Learning Objectives At the completion of this lab you be able to: Launch Microsoft Excel and create a new Excel spreadsheet. Add toolbars to the Microsoft Excel program interface. Format and align text and numbers. Insert formulas. Insert functions. Understand absolute and relative cell referencing. Insert charts within Excel. Sort data using an Excel spreadsheet. Perform cell protection.

2 Technical Terms.xls(x) : The file extension for a spreadsheet document that has been created in Microsoft Excel. Cells: The idea of cells on a spreadsheet may seem too simple to define but there is one thing that should be kept in mind that aids in the overall understanding of how to use cell referencing in a spreadsheet. Each cell reference you are given is a combination of a column reference and a row reference. For example cell A1 can only be found by first finding column A and then row 1. Keep this in mind when trying to understand and use absolute and relative cell referencing. Formulas: Formulas are the third type of data to be found in an Excel spreadsheet, the first two being text and numbers. All formulas and functions begin with an equal sign. For example the formula =A1 + B1 would add the two numbers found in cells A1 and B1. You would enter this formula in the cell where you want the result to be viewed. Functions: Predefined formulas that perform calculations by using specific values, in a particular order or structure. For example, the SUM function adds values or ranges of cells, and would take the form of =SUM (A1:D1). The average function would take the form of =AVERAGE (A1:D1), and would find the average of the numbers between the range of cell A1 and D1. There are literally hundreds of functions available for use within Microsoft Excel and they can all be seen if you select Function from the Insert menu. Operators: Refers to the symbols used to represent the basic mathematical concepts that we are already familiar with such as addition, subtraction, division and multiplication. In Microsoft Excel these operators can be added to a formula or a function by using the following symbols +, -, /, and *. Range: Refers to the number of cells within a given area and is represented by the following symbol, :. For example the range of A1:D1 would include the cells A1, B1, C1, and D1. Toolbars: A series of selectable buttons in either a horizontal row or a vertical row that give the user another option aside from pull-down menus.

3 Key Concepts Formatting text and numbers To enter information into a spreadsheet, click the mouse on the cell where you want data to appear, then type. Notice that if a cell is not wide enough to hold the text you type, the text simply spills into the adjoining cells to the right. We can fix this by merging and centering our data across our columns and rows; we will do this later on in the tutorial. Also notice that anything you type into a cell text, number, or formula appears in the formula bar as shown below: Adjusting columns and rows Quite often, when typing in column and row headings or in general any form of text, the amount of data goes outside the boundaries of the rows and columns on our spreadsheet. Of course it is possible to widen columns or rows so that all data is completely visible. To do so place the mouse on the boundary between the columns or rows, the cursor should turn to a double arrow as shown in the picture below.

4 Once the cursor appears similar to image shown above columns or rows can be resized by clicking and dragging the mouse until the row or column is the correct length. Multiple Sheets An Excel spreadsheet file is technically referred to as a Workbook and can contain several individual spreadsheets called Worksheets. This feature allows you to organize various kinds of related information in a single Excel file. At the bottom of the Excel screen are Sheet tabs. To move from sheet to sheet, one can click the sheet tabs. If you click on Sheet2 or Sheet3, you will see that they are separate blank spreadsheets. To rename a sheet, double-click the sheet name on the sheet tab, then type a new name over the current name. To delete a sheet, right-click on the sheet tab you want to delete, and select Delete from the context menu.

5 Performing Calculations In Excel The real power of spreadsheets is performing calculations. If you are not going to use formulas and functions in a spreadsheet, you might as well just use a word processor and create a simple table to format information. When performing calculations in Excel sometimes you will need to use a formula and sometimes you will need to use a function. After reading the information below you will have a better idea as to when to use one or the other. Formulas In Microsoft Excel formulas are simply equations that make use of arithmetic operators and that the mathematical rule of order of operations applies. In order to properly use formulas all formulas must start with an equal sign, e.g. =B5-B20. When typing in formulas, the formula should be typed where you want the result to be displayed. For example in the sample sheet below to calculate the first percentage the correct formula would be, =A2/B6 and the formula would be typed in cell B2.

6 The mathematical operators that can be used in formulas are as follows: * = Multiplication / = Division + = Addition - = Subtraction Functions In Excel functions are predefined built-in formulas that perform calculations by using specific values, called arguments, in a particular order, or structure. For instance the SUM function can be used inside Excel to add up all the values in a range of cells. In the following example the SUM function is being used to add all the values in cells A1, A2 and A3. Note how the function is formatted e.g. =SUM(A1:A3). A1:A3 indicates a range from A1 to A3 and includes all cells within that range. In order to get this function to work properly the function does not have to be typed in manually as you see it below. As the person typing in the function all you have to do is decide what values to include in your function and Excel will use the function wizard to type out the function correctly for you.

7 Excel has literally hundreds of functions available for use depending upon what type of sheet is being created and what type of data is being used. The convenience of using these functions means you don t have to be a math expert or even an expert at using spreadsheets to decide which function would be best to use and how to use it. As the person creating a spreadsheet all you have to decide is what you want to do with your data and then look for a function that is capable of carrying it out. Some of the more advanced functions are called conditional functions. Conditional functions can return a different result based on a certain condition being met or not met. Examples of this type of function include the IF and COUNTIF functions. The IF function compares one value to another value and then gives a result based on the results of that comparison. For example you may decide to use an IF function if you wanted to see whether or not a group of students has met a certain minimum level achievement i.e. whether they have passed or failed an exam.

8 In the following example the data for three students has been entered based on their results for an assignment. Based on those results a Percentage was determined by dividing the Raw Score by the value the assignment was marked out of, in this case 50. In this case the IF function is going to be used to determine whether or not the students pass or failed the assignment with 50% being cutoff for pass/fail. This may seem very complicated at first, but by using the function wizard in Excel it actually becomes easier than first perceived. Once you have chosen to insert the IF function you are presented with the following screen. As you see there are three values that need to be entered; the Logical_test, the Value_if_true, and the Value_if_false.

9 The Logical_test is in fact what is being tested, or put more simply the condition being evaluated to true or false. In this example what is being tested is whether or not the student mark is over fifty percent. If it is over fifty percent they pass if it is not then they fail. So going back to the example where the students percentage is being evaluated, the value for the first students percentage is in cell C3. So in this case the value that would be typed in to the Logical_test line would be C3>50%. The > symbol used here means greater than. The Value_if_true is the result that will be displayed if the condition is found to be true. So in this case if the value is greater than 50% the value will be Pass. The Value_if_false is the result that will be displayed if the condition is found to be false. So in this case if the value is less than 50% the value will be Fail.

10 Remember, when the Insert Function wizard is being used, all that has to be done is the entering of the values. Once the OK button is clicked Excel will make sure that the function is typed in correctly to give us the correct result. In the above example the formula was typed in for the first student and then copied down to get the results for the remaining two. In order to get the correct results when copying formulas correct cell referencing must be applied. This is covered in the next two sections. Cell referencing in formulas and functions There are two types of referencing you have to consider when entering in formulas and functions: relative and absolute. Using either relative or absolute cell referencing in formulas will ensure that the formula or function that has been entered to achieve one result will yield a similar result when copied for the next set of data i.e. a formula that will find the final mark for all students. A relative cell reference is automatically adjusted when copying a formula to other cells. For example, if the following formula, = A1+B1 was copied, from cell C1 down to C2, the formula when copied would change to = A2+B2.

11 Note the cells in cell C1 and C2 contain different answers. Notice the row references in the formula, i.e. the numbers 1 and 1, got bigger by one when copied down one row. True, this formula could have simply been typed in to reflect this change, however it is much easier to copy the formula, consider the case when you have to copy the formula down many rows. An absolute cell reference refers to a value that does not change when being copied to other cells. For this example the same formula as above will be used but with one small change: absolutes will be added to the row values in the formula. In Microsoft Excel absolutes are represented as dollar signs, $). Note that cells C1 and C2 contain the same answer. This is because the formulas in both the cells are adding cells A1 and B1. The dollar signs in front of the 1 and the 1 ensure that the values for the rows will remain the same as the formula is copied down. Auto-Fill/Copying formulas The reasons for correctly using absolute and relative cell referencing in our formulas is so that they can be copied easily from one cell to another and work as expected. Being able to copy formulas and not type them in repeatedly will save a lot of time and work when working on a given spreadsheet.

12 To display the copying procedure the following sample data will be used. Once the correct formula has been entered into cell C2 that will add cell A1 and B2 (note the use of both relative and absolute cell referencing): Because the formula is being copied down rows we should add the absolute in front of the 1 in the cell reference A1. To copy a formula, click on the bottom right-hand corner of the cell that needs to be copied (in this case C2), and a little black crosshairs will appear. Drag down to include the last two cells in our range, C3 and C4. Release the mouse and we see our formula successfully copies with the correct results in our chosen cells. Cell Comments Cell comments are additional explanatory notes, which you can attach to any cell in a spreadsheet. Cell C3 in the following sample spreadsheet has a cell comment associated with it, as indicated by the small red triangle in the upper right corner of the cell. To view the comment, rest the pointer over the cell. A text box will appear as shown below:

13 Sorting Data in a spreadsheet can sometimes be more meaningful to the person viewing your sheet if it appears in a certain order. With the sorting tools in Microsoft Excel, you can sort rows of data according to the contents of one or multiple columns. The first step in performing a sort in Excel is to select the data you wish to sort. This may seem like a very straightforward step, however one very common sorting mistake is the incorrect selection of data to be sorted. For example if a teacher wanted to rank the following students in descending order according to their final mark, in order to conduct a proper sort, that teacher would have to be sure to select the entire range of data that will be affected by the sort and not just the student names or the final mark. If the following data was sorted only the data for the Final Mark column would be sorted leaving the data in Student column and ID Number column unsorted. If the following data was sorted the data in the Student and ID Number columns would be sorted based on the data included in the Final Mark column.

14 Result of an incorrect sort note that the names of the student no longer correspond to the correct final mark. Result of a correct sort. Note that the same students are receiving the same final mark from before the data was sorted. Cell protection In Excel, cell protection options are applied to a cell or to a set of cells to prevent editing (or even viewing) all or parts of a worksheet. This can be very useful when you are sharing a spreadsheet with others or even to prevent yourself from accidentally altering labels, formulas, etc. once they are all completed. In Excel to apply this protection the cell you wish to protect has to be locked and the entire spreadsheet then has to be protected. Only if both the cell is locked and the sheet protected will the data inside that cell be unchangeable. Steven Scott & The EDIT 202 Development Team University of Alberta