Spreadsheets

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Spreadsheets

• Introduction

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What is a spreadsheet?

• A spreadsheet program is used to manipulate
  numbers
• One of the most popular spreadsheet programs is
  Microsoft Excel

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What is in a spreadsheet?

• A spreadsheet is made up of
• Cells
• Rows
• Columns
• A spreadsheet look like this -

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Cell contents

• Each cell can contain
• A number (a value)
• Text
• A formula

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Formula

• In Excel a formula always starts with
• A formula can be
• simple
• complex
• conditional

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Examples of formula

• Simple D1C1
• Complex LEFT(D5,7,2)
• Conditional IF(D5gt50,pass,fail)

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Functions

• A function is an inbuilt formula.
• eg
• SUM(B5B10)
• AVERAGE(B5B10)
• MAXIMUM(B5B10)
• MINIMUM(B5B10)

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Formatting

• To change how something looks, we change its
  format
• We can change the look of
• the cell itself
• border, background colour
• the attributes of the cell
• number of decimal places, currency
• We can change
• the column width
• the row height

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Insert column/row
If we need to add data to a particular part of
the spreadsheet, we can insert a column or a
row. Once the column or row is inserted, we need
to add the data. When a column or row is
inserted, the formulae are automatically updated.
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Calculation

• Calculation can be
• automatic
• manual
• Automatic recalculation means that all the
  formulae in a spreadsheet are recalculated every
  time a change is made to the spreadsheet.

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Manual Calculation
Manual recalculation means that the formulae in a
spreadsheet are only recalculated when the user
presses a certain key. This feature is used when
the user is typing in a large amount of data.
Automatically recalculating the formulae after
every entry would make the data entry very much
slower.
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Cell protection
Cell protection is used to prevent the user from
changing the contents of a cell (it locks the
cell). In a spreadsheet, the column and row
headings and the formulae are usually protected.
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Example of cell protection


Protected cells
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Replication

• Replication is used to make a copy of a formula.
• Theer are two types of replication
• relative
• absolute

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Relative Replication
When we copy the formula down a column, the cell
references change to be appropriate for that row.
C3 changes to C4 changes to C5 changes to C6
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Absolute Replication
When we copy the formula down a column, the cell
reference does not change. It stays absolutely
the same
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Example of Absolute Replication
C5 changes to C6 changes to C7 changes to C8 B1
does not change In Excel, the sign before a
letter or number in the cell reference means that
it does not change when replicated.
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Charting
The data in a spreadsheet can easily be shown as
a chart. A graph or chart is used to present
facts in visual form. It should be used to make
facts clearer and more understandable It is
easier to spot a trend or pattern in a chart
than in a table of numbers.
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Example of charting
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Example of a trend
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Spreadsheets

• End of presentation