# © Keith Vander Linden, 2005 1 How did you ever do without it? - from the first VisiCalc ad, 1979.

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© Keith Vander Linden, 2005 1 How did you ever do without it? - from the first VisiCalc ad, 1979

© Keith Vander Linden, 2005 2 Accountant’s Paper Ledger image from Grauer&Barber, Excel 2003, Prentice Hall, Oct., 2004 2-Dimensional representation of accounting data

© Keith Vander Linden, 2005 3 ● 1979 ● Visible, interactive accountants ledger ● Developed for the Apple II ● A “killer” business application for the personal computer Dan Bricklin (1951-) VisiCalc images from www.bricklin.com, Oct., 2004www.bricklin.com

© Keith Vander Linden, 2005 4 ● 1982 ● Included charting and plotting ● Wildly successful Mitch Kapor (1950- ) Lotus 1-2-3 images from www.kapor.com and www.nb-info.co.uk, Oct., 2004www.kapor.comwww.nb-info.co.uk

© Keith Vander Linden, 2005 5 ● 1985: Originally written for the Mac ● 1987: Shipped with introduction of Windows ● Graphical interface Bill Gates & Microsoft Excel images from www.microsoft.com, Oct., 2004www.microsoft.com

© Keith Vander Linden, 2005 “What if?” ● The biggest advantage a spreadsheet has is the ability to ask the “what if?” questions (and get a quick answer). ● Be very, very lazy (in the long run): – Use equations to compute answers as much as possible. – “What if” questions answered by tweaking the data. 6

© Keith Vander Linden, 2005 7 Spreadsheet Cells ● Worksheets are 2-dimensional arrays of cells. ● Each cell is referred to by its cell reference. – Examples: A1, E10, AZ1024 ● Cells can be grouped as a range. – Examples: A1:E10, C5:Q8

© Keith Vander Linden, 2005 8 Spreadsheet Values ● Constants/literals – A number – A text label ● Formulas (always begins with an = ) – Numbers – Arithmetic ( +, -, *, / ) – Functions ● Worksheet contents are updated in real time.

© Keith Vander Linden, 2005 Be Very, Very Lazy ● This usually means doing some work up front. – Can easily ask “what if?” – Compute correct answers. ● Guidelines – No numbers in formulas. – sum() and average() should refer to ranges. 9

© Keith Vander Linden, 2005 10 Relative/Absolute Addressing ● When cells are copied: – relative addresses are modified automatically – absolute addresses always refer to the same cell ● Syntax: – Relative address: A1 – Absolute address: \$A\$1 ● Use the F4 key!!

© Keith Vander Linden, 2005 11

© Keith Vander Linden, 2005 12

© Keith Vander Linden, 2005 13 Spreadsheet Issues ● Powerful tools can create powerful problems.

© Keith Vander Linden, 2005 14 Technology and Humanity ● Working with technology can be dehumanizing. ● “Be fruitful and increase in number; fill the earth and subdue it.” - Genesis 1:28 What’s the Big Idea

© Keith Vander Linden, 2005 15 Graphs and Charts ● Quantitative data can frequently be illustrated in a compelling way using charts and graphs. ● Spreadsheet systems usually provide graphing and charting capabilities. ● Here are some examples.

18 image from VDQI, 1983

© Keith Vander Linden, 2005 19 Chart Types ● Pie charts ● Column/bar charts ● Line charts ● Maps

© Keith Vander Linden, 2005 20 Graph/Chart Issues ● Data values can, however, be obscured or misrepresented using charts. ● Here are some examples.

23 image from VDQI, 1983

© Keith Vander Linden, 2005 24 image from VDQI, 1983

© Keith Vander Linden, 2005 25 image from VDQI, 1983

© Keith Vander Linden, 2005 26 Lying graphics cheapen the graphical art everywhere … When a chart on television lies, it lies millions of times over; when a New York Times chart lies, it lies 900,000 times over to a great many important and influential readers. VDQI, p. 53-79 Edward Tufte (1940-) VDQI, 1983 images from www.edwardtufte.com, Oct., 2004www.edwardtufte.com

© Keith Vander Linden, 2005 27 from Calvin College Chimes, Oct. 6, 2000

© Keith Vander Linden, 2005 28 from Calvin College Chimes, Sept. 29, 2000

© Keith Vander Linden, 2005 29 image from Exploring Microsoft Excel 97, Grauer & Barber, 1998

© Keith Vander Linden, 2005 30 image from Exploring Microsoft Excel 97, Grauer & Barber, 1998

© Keith Vander Linden, 2005 31 Using Charts/Graphs Properly ● Decide what you want to present. ● Present it accurately and unambiguously. – Let the graphic values/change accurately depict the data values/change. – Clearly label all relevant details. – Don’t graphically mix dissimilar elements. – Use the right type of graph. – Don’t add “chartjunk”.

© Keith Vander Linden, 2005 32 Technology and Lying ● It is as easy to lie or mislead with technology. ● “When he lies, he speaks his native language, for he is a liar and the father of lies.” - John 8:44 What’s the Big Idea