Chapter 10 - Spreadsheets

Chapter 10 - Spreadsheets

1. A spread sheet application such as Excel can store all its data in a single file (with an .xls extension). This file is called a 'workbook'.

   • A workbook is made up of one or more 'worksheets'. A worksheet is a single tab in the spreadsheet workbook.

2. Cells

   • A cell reference always starts with a letter and ends with a number e.g. A5 or H28
   • A range of cells is a set of cells in a row or column
   • Data entered into cells can be different data types e.g. text, number, currency, date, percentage etc.
   • Each cell can contain:
     •  Labels – any text in a cell describing the data in a row or column(titles, headings that identify data)
     •  Data – any values (text or numbers) that are entered for the use of calculation
     •  Formulas and functions – mathematical calculations carried out automatically

3. Formulas

   • Must start with an =
   • Formulas perform calculations on cell contents.
   • Formulas appear in the formula bar.
   • The result of a formula is automatically recalculated every time the data on a spread sheet changes.
   • 4 main mathematical operations
     • / Divide
     • * Multiply
     • - Subtract
     • + Add

4. Functions

   • Must also start with an =
   • Functions are part of spread sheet software. They are specialised calculations built in to the spread sheet software.
   • Function name describes what a function can do SUM, COUNT, AVERAGE, MIN, MAX, IF

5. Formatting

   • The content of a cell can be formatted:
     • Font style, size, colour, border style, alignment, cell colour.
     • Multiple cells can be merged in to one cell
   • Cells are often formatted to reflect the data that is held in them. Data types include:
     • Currency, number, real, integer (whole number), date, text

6. Replicating cells

   • When you position the mouse pointer in the bottom right hand corner of the cell and drag down or across the spread sheet tries to respond intelligently. If there is a formula in the cell, the spread sheet tries to adjust it as it goes down the page to fit in with the new position and the cells being referred to.

7. Graphs & Charts

   • Using charts/graphs allows us to notice patterns & trends more
   • Specific data can be selected on a spreadsheet and a chart/graph of this data can be created.

8. Cell Referencing

   • When a formula is copied by ‘filling down’ the cell references in cells are adjusted as you drag the pointer down the page.
   • Relative cell references: If a formula is copied by filling down, the cell references are adjusted as you drag the replication pointer down the page. This is because it uses the relative address of the cells based on their position in the worksheet
   • □ Absolute cell references: Some we need to use part of a formula that does not change. For example is VAT was recorded in B2 as 20% then the B2 part of the formula must not change because the rate will be 20% for everything. All the other cell ranges will change. When the formula is copied down, the relative address changes but the absolute doesn’t.

9. ‘What if?’ calculations - Changing the data in a spreadsheet model allows you to make and test predictions. You may explore what would happen to your profit if VAT changed to 30%. These are known as what if calculations. They allow you to use a spreadsheet to see what would happen if certain figures changed in a spreadsheet.

10. Advantages

    • Automatic recalculation - Every time the content of a cell is changed, calculations are performed and other cells are updated if necessary.
    • Accurate calculations - Providing the formulas have been set up correctly, the formulas will always produce a correct calculation
    • Graphs/Charts - Can be drawn using data in selected cells. Replication - Once the first formula is correctly entered, it is possible to drag across to adjacent cells in a row or column so the computer copies the pattern of the calculation.
    • What if calculations
    • Formulas can be reused and stored
    • Calculations involving large numbers are possible