Introduction to Spreadsheets

transcript

Bent Thomsen

What is an electronic spreadsheet?

It is the electronic equivalent of an accounting worksheet, comprised of rows and columns to allow you to do many tasks in the organization of numbers in a clear, easy to understand format

What is an electronic spreadsheet?

• It is a tool to help you calculate budgets, do economic analysis, statistics, planning, engineering calculations, …

• Replaces pen, paper and pocket calculator• Can show diagrams and graphs• Can input data from other programs• Can output data to other programs

Some Advantages of Spreadsheets

• Spreadsheets are capable of exploring “what-if”scenarios (e.g. budgets, submitting bids)

• Once it is set up properly, the user can save time by never having to set up the spreadsheet again– Blank spreadsheets are called templates.– Monthly salaries,grade sheets

Spreadsheet terminology• Row - horizontal axis (designated by numbers)• Column - vertical axis (designated by letters)• Cell - intersection of row and column

(designated by an address comprised of the column letter and row number e.g. A1)

• Block//Range - a rectangular group of one or more cells (identified by block coordinates (e.g. A1:G4)

Spreadsheet terminology (con’t.)• Label - alphanumeric• Value - a number or formula result• Formula - creates relationships among other cells• Template - a notebook that has labels, formulas,

and all of the formatting but no actual data (e.g. actual figures and numbers)

How big is a spreadsheet?

• Normally you see 9 columns and 18 rows• = 162 cells• One sheet has 256 columns and 65536 rows• = 1677216 cells• That is more than 103000 screens• Would take 34000 A4 pages to print• Take 194 days to fill at one cell pr second

Exploring the Excel ScreenTitle bar

Menu toolbar

Standard toolbar

Screen Tip

Active worksheet in workbook window

Formatting toolbar

Task Pane: organizes related

commands

Activating Toolbars

Click on View and Toolbars

Toolbars sub-menu appears

Click on desired toolbar

Check indicates active item; click to

deactivate

Moving Around the Worksheet

Working in an active cell(intersection of a row and column)

Cell pointer

I-beam: to place

insertion point

Insertion point: where text will be

entered

Moving Around the Worksheet• Move cell

pointer – arrow keys– scroll bars

• Change pages – click on tabs– tab scroll

buttons

Moving Around the Worksheet• Consider cell B4 active• Note

– thick cross mouse pointer– row, column buttons highlighted

• After scrolling to right, note … – row button still highlighted– name box still shows B4 as active cell

Moving Around the Worksheet

To select a column

•Click on the column heading button

•Whole column is highlighted

Entering Labels• Click desired cell to make it active• Label is displayed both in cell and in formula bar as you type• Label displays out of its column

– as long as other columns are empty

Worksheet with Labels

• Note – Documentation

section– Label cut off, next cell

occupied– Labels aligned left

Editing a Cell's Information

• Click on desired cell– Cell pointer moves there– Contents displayed in

formula bar• Click mouse pointer

(I-beam) to location within text– type, delete, copy, paste

as needed

Entering Values

• When entering numbers– do not use commas– numbers are right justified by default

• To proceed to next cell right use [Tab] or right arrow key

• To proceed down, use [Enter] key

Entering Formulas• Formulas are mathematical equations

– perform calculations– always start with an equal sign (=)

• Formula shows informula bar

• Note color referencesin formula

Entering Formulas• After formula entered and cell pointer moved

– Formula does not show in formula bar

– Result of calculations shows in cell where formula entered

Operators

• ^ - exponents• + - addition• * - multiplication• / - division• - - subtraction• = - function

Order Calculations are Performed

• First exponents• Then any multiplication and division in the

order they occur• Then any addition and subtraction in the

order they occur

Parentheses

• Operations within parentheses are performed before those outside.

• Within the parentheses the basic rules are followed.

• Multiple sets of parentheses, the innermost are executed first followed by the next set.

Built-in functions

• Functions are pre-written formulas• Functions must start with an equal sign• Functions takes value(s), perform an operation,

and returns a value(s)• Values you use with a function are arguments• =AVERAGE(D3:D7)

– AVERAGE is the function– D3:D7 is the argument

Using Functions• Advantages of predefined functions

– save time– more accurate

• Using AutoSum– Click cell at

bottom of column

– Click AutoSumbutton

– Excel assumesit should totalthe column

– SUM functioninserted

Using Functions

• AutoSum can also be used to right of a row of numbers

Using Functions• Note end results of

using AutoSum• Note:

– Click AutoSum button once to display formula,again to apply

– SUM formuladisplays in Formula bar

Using the Function Insert Feature• Click on Insert, and Function• Insert Function dialog box appears

Select function category

Choose specific function desired

Using the Function Insert Feature

Note calculated result of inserted function

Animated border shows selected

Formula appears in

Arguments of function must be

specified

Using the Function Insert Feature

Note calculated result of inserted

function

Creating a Chart

• Select series of numbers from worksheet

• Click Chart Wizard button– Dialog box opens

• Choose charttype, sub-type– Note preview

button

Click on Next button to proceed

Creating a Chart

• Step 2– Review and change

series range asneeded

– Click CategoryLabelsbutton to specifysource of labelsfor chart

Creating a Chart

• Labels now show inlegend

• Range for labelsnow displayed

Click on Next button to proceed

Creating a Chart

• Step 3– Enter titles (which

will show on preview)– Specify legend details

on legend tab– Specify Data Label

details as shownClick on Next

button to proceed

Creating a Chart

• Step 4– Specify where chart will appear

– Click Finish

Creating a Chart

• Chart is displayed as object in worksheet

Note Chart toolbar displayed while chart is selected

Statistical analysis in Excel• you can do a range of statistics in Excel using the

‘Analysis ToolPak’• you can calculate a correlation matrix and undertaking

regression analysis• results of this analysis goes on additional sheets in the

Excel workbook. remember to save this workbook often (as a .xls format file)

• note, Excel is powerful but it is not a statistics package. Alternatives are SPSS and Minitab which are full function statistics packages and will do lots more. they will read Excel spreadsheets and dbf format data files

Opening the ToolPak, Excel’s data analysis add-in

go to ‘Tools’ -> ‘Add-Ins’

choose ‘Analysis ToolPak’and click ‘OK’

Correlation analysis• are A and B related?• correlation coefficient provides a single

numerical value describing a linear relationship, telling us the direction and strength Percentage Limiting Long Term Illness against Percentage No Car

0 10 20 30 40 50 60 70 80 90

Percentage No Car

• you can get Excel to addthe ‘best fit’ line (Trendline)through the scatter of points• to do this select the data pointson the chart, right-click andchoose ‘Add Trendline’

• In the ‘Add Trendline’ boxchoose ‘Type’ - ‘Linear’ andclick ‘OK’

Percentage Limiting Long Term Illness against Percentage No Car

0 10 20 30 40 50 60 70 80 90

Percentage No Car

• now we want to calculate the actual Pearson’s correlationcoefficient (the r value) for this relationship• it is very easy to calculate with Excel

What do you think r will be??

• go back to the ‘Tools’menu and select ‘Data Analysis’

In the ‘Data Analysis’window choose‘Correlation’

Correlation analysis• this window allows you to define the variables you wantto correlate• you will correlate all yourcensus variables to get a fullcorrelation matrix

• the ‘Input Range:’ box defines the columns in the spreadsheetyou want to run the correlation on. click in this box and thenwith the mouse select all the columns of census data•check the ‘Labels in First Row’ box as well. make sure the ‘New Worksheet Ply:’ option is checked and call it ‘correlation’and then click on ‘OK’

Steps in Developing a Spreadsheet

1.Determining the purpose - what inputs, what outputs, what printed reports

2.Planning - plan it on paper first

3.Building and testing - make sure it manipulates the data correctly

4.Documenting - should include something within the worksheet itself (directions, name and date)

Introduction to Spreadsheets

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