Spreadsheets

Foundation Computing

All those who believe in psycho kinesis,raise my hand.

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QuizWhat is an interface?

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Quiz (2)What is special about the USB interface?

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Why Spreadsheets?

Word processor Processing words, layout of text, spell check

Calculator Arithmetic calculations

Spreadsheet Tabulating data and calculations on the data,

analyse and present data

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Why Spreadsheets? (2) Collating and processing numeric data, eg

Student marks Results of an experiment

Financial analysis, eg Budgets Understanding financial results

Visualizing data, trends, etc Charts

Schedules, timetables, etc

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HistoryIdea: Dan Bricklin (while a Masters

student at Harvard)VisiCalc (1979)

Dan Bricklin + Bob FrankstonApple II

MS ExcelOpenOffice

Spreadsheets

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What is a spreadsheet?Developed to do financial computations in

a page layoutSimilar to a bookkeeper’s ledger

Rows and columns of numerical data

But different Stores formulas as well

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Terminology In Excel, a spreadsheet is called a worksheet An Excel file contains a workbook that is a

number of worksheets Each worksheet is a huge grid of cells Each cell is identified by its column (a letter)

and its row (a number), eg A1 (example)

What is a spreadsheet? (2)

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See also short video “workbook” from lecture webpage

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The cell Each cell has a content, which can be

a constant such as a label (text) or a value a formula that calculates the value

and a format, which controls how the content is displayed

An operation applies to a single cell, or to a range of cells, such as a complete row or column

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The cell (2)

Content Labels give numbers meaning

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The cell (2)

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The cell (2)

Content Labels give numbers meaning

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The cell (3)

Values, egNumbersPercentagesCurrency (money values)DatesTimesText

Type determined by how written or manually set (example)

Formulas (later)

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See video “Book2“ on lecture webpage

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The cell (3)

Values, egNumbersPercentagesCurrency (money values)DatesTimesText

Type determined by how written or manually set (example)

Formulas (later)

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The cell (4)Format

Font, size, colour, (text and background) (example)

Shading, borders You can also control

Column widthRow height (example)Merged cells

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See video “format” on lecture webpage

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The cell (4)Format

Font, size, colour, (text and background) (example)

Shading, borders You can also control

Column widthRow height (example)Merged cells

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expenses.xls

Using Spreadsheets

Merged cells

Active cell D8

labels

labels

values (currency)values (dates)

Formula result

Formula

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Using Spreadsheets (2)

Cell Reference Single cell: Row and column, eg A1

Range of cells Rectangular

group of cells, eg A1:A3, or A1:B2 (top left:

bottom right)

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Using Spreadsheets (3)Select a range by

Click-dragging across the cells SHIFT-clicking on the corner cells Clicking on an entire row/column Typing in the addresses of corner cells,

separated by a colon

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Using Spreadsheets (4)When multiple cells are selected, we can

Change the format for all these cells Merge these cells Copy/cut the contents and paste elsewhere Delete the contents of all these cells (example)

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Using Spreadsheets (5)For a complete row/column, we can

Delete the entire row/column Insert a new row/column before/after Change column width or row height

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Formulas

Formulas Two views

FormulaValue in cell

To see a cell's formula, make it the active cell then look at the formula bar

Start with = Example =A1

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A simple formula

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Formulas

Formulas Two views

FormulaValue in cell

To see a cell's formula, make it the active cell then look at the formula bar

Start with = Example =A1

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Formulas (2)

Arithmetic operations Example =A1+1

(Compounding interest)

=A1/A2divide/=A1*A2times*=A1-A2minus-=A1+A2plus+

ExampleMeaningArithmetic Operator

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Interest example

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Formulas (2)

Arithmetic operations Example =A1+1

(Compounding interest)

=A1/A2divide/=A1*A2times*=A1-A2minus-=A1+A2plus+

ExampleMeaningArithmetic Operator

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Functions

Examples =AVERAGE(A1:A3) =SUM(A1:A3) =COUNT(A1:A3) =IF(A1>0,"Positive","Negative")

Test with true and false options

There are many more!!! (example)

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Functions

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Sum example

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Functions (2)

Predefined in spreadsheet applicationPerform common tasksArguments as input

value cell reference cell range results from other functions

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IF function example (1)

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If function example (2)If function within a function

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Functions (3)Example

You may get an exam question like this!

What value will appear in cell C3?

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If function again

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Copying Formulas

Often in a table we find that a range of cells, eg. a column, share the same formula.

There is a shorthand way of doing this: Enter the formula in the first cell Use the fill handle to drag the formula into adjacent

cells, or Select the range of cells and use the fill menu or fill

keyboard shortcut. (example)

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See video “IF copy” on lecture webpage

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See video “absolute reference” on lecture webpage

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Copying Formulas (2) Sometimes filling a formula doesn't do what we

expect. Why? A formula contains addresses of other cells. Normally these are relative addresses which get altered

when we fill the formula. Sometimes we want these to be absolute addresses so

that they don't change when we fill the formula. Put $ into addresses.

(example)

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Absolute addresses Fixed column $A1 Fixed row A$1 Both fixed $A$1

Copying Formulas (3)

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Open file “abs_rel_example” on lecture webpage

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Open file “abs_rel_example” on lecture webpage

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Open file “abs_rel_example” on lecture webpage

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Open file “abs_rel_example” on lecture webpage

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Charts

Used to visualize results Bar/Columncomparison of values Line trend over time Pie proportions Chart Wizard Highlight values and labels (hold control) Start wizard (examples column and pie chart)

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Charts (2)

Can include a spreadsheet into another document, eg. Word, PowerPoint

Use "Paste Special" to choose between: Embed a COPY of the spreadsheet into the document or Insert a LINK to the spreadsheet into the document

Consider portability issues with Object Linking and Embedding

(example)

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Charts (3) There are a wide variety of graphs and charts

available in Excel FIRST decide what you want to show with a chart

or graph! Understand what your data means! Use the Chart wizard to build your chart or graph Play with alternatives but make sure your chart or

graph makes sense!

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Charts (4) Axis scale, labels etc. Note that an axis can have

a date/time scale Gridlines Legend for categories or lines Actual data value or labels on the chart Colours, patterns, 3D effects Chart title In own worksheet or superimposed on an existing

worksheet

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Printing and page setup Can include headers and footers Can force a worksheet to fit on a single page or

one page wide Can print just a range of cells on a worksheet Can choose to print or not print grid lines Can repeat selected rows (or columns) on every

page, eg. headings Use PREVIEW! Can rename sheets

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Final word of warning Spreadsheets are a wonderful aid to analysing

and understanding data HOWEVER, it is very easy to make an error in a

spreadsheet formula and to not realise that it is telling you the wrong answer

Always check a sample of your spreadsheet Calculations by hand using a calculator!