Introduction to Spreadsheets Presented by Frank H. Osborne, Ph. D. © 2005 Bio 2900 Computer Applications in Biology

Basic Considerations A spreadsheet is basically a sheet of paper with columns and rows like you would use to keep business records.

Basic Considerations The columns and rows form a grid. Each column has a letter at the top and each row has a number at the side.

Basic Considerations Where each column and row intersect is a cell. In this picture the cursor is in cell A1.

Basic Considerations A typical computer spreadsheet has 256 columns identified as A through IV and rows. This gives a total of 16,777,216 cells. A cell contains data. Data can be –constants (numbers) –labels (such as column headings) –formulas (for calculations)

Basic Considerations Spreadsheets are useful in a variety of disciplines. These include: –business - for financial records –science - for data analysis and calculations –math - for graphing, formulas and statistics Spreadsheets are used in all disciplines where data analysis, graphs and charts are needed.

Spreadsheet Data Types Constants –Constants are numbers. Numbers may be whole numbers or decimals. –Numbers can also be currency, fractions, scientific notation, and percentages

Spreadsheet Data Types Labels –Any type of text, such as column headings or identifiers in lists. –Text can have a variety of fonts and pitch sizes. –Cells can have borders and underlines. –Cells can have different colors than the background for emphasis purposes.

Spreadsheet Data Types Formulas –Formulas are used for calculations. All formulas must begin with the equals (=) sign. –When a formula is in a cell, the spreadsheet displays the value of the formula, not the formula itself. –You can see the formula in the formula bar.

Command Menus Command menus are located on the top program line, just below the title line. The menus include File, Edit, View, Insert, Format, Tools, Data, Window and Help

Command Menus File Menu –Contains file commands –New: makes a new workbook –Save: saves a workbook –Save As: saves file under a new name –also contains Print commands

Command Menus Edit Menu –Contains editing commands –Undo: permits to reverse a mistake –Cut, Paste: allow moving parts of a worksheet to another part of the workbook or to another file

Command Menus Insert Menu –Can insert rows, columns and extra worksheets –Allows to insert charts and graphs –Can insert pictures and graphics, diagrams and other objects

Command Menus Format Menu –Permits formatting of cells, rows, columns or entire worksheets –Formatting can be numeric, dates, text, time, currency, accounting or a variety of others

Command Menus Tools Menu –Spell checking –Cell and worksheet protection –Data analysis

Command Menus Data Menu –Sort is most commonly used –Ascending order means that the smallest item comes first and the largest is last –Descending order means that the largest is first and the smallest is last

Command Menus Window Menu –Allows you to work with multiple windows at the same time. –Windows can be different files or different parts of the same file

Command Menus Help Menu –Help menu offers help and explanations about the product –With some products, help is also available over the Internet

Some Simple Worksheets We will do some simple worksheets in class –List of school supplies –Basic statistics on some test grades –Histogram

Some Simple Worksheets List of School Supplies

Basic Statistics Excel has a variety of mathematical and statistical functions built in. To illustrate these, we will do basic statistics on some data and make a histogram. The first thing to do is to open a new workbook and enter the data.

Basic Statistics Data Entry The data are entered in a single column. The heading on the column is optional. In this example we are using some test grades.

Basic Statistics On the command line select Tools followed by Data Analysis

Basic Statistics In the Data Analysis dialog box select Descriptive Statistics.

Basic Statistics In the Descriptive Statistics dialog box enter the input range ($A$2:$A$28) and check Summary Statistics.

Basic Statistics The results appear on a different worksheet.

Basic Statistics Adjust the column widths for legibility.

Basic Statistics Adjust the column widths for legibility.

Histogram The histogram provides graphical representation of the distribution of the data. It looks like a column (bar) graph. It is important that all bars touch each other so as to assure that all data are included. Begin by entering and sorting your data.

Histogram The data are entered as before. Or, make a copy of your data on another worksheet. Highlight the data range.

Histogram On the command line, select Data followed by Sort.

Histogram In the Sort dialog box select Ascending order.

Histogram Once the data are sorted, they are broken into groups called Class Intervals or Bins. You should divide the groups counting by 5s, 10s or 20s. Make a column for your class intervals. In the adjacent column put how many there are in each group. This is the frequency.

Histogram Data are grouped in class intervals of 10s. A frequency table is prepared.

Histogram First, the data values in the frequency table are highlighted.

Histogram On the toolbar, select the Chart Wizard icon.

Histogram From Chart Type, select Column. Press Next.

Histogram As you already highlighted the data, they are automatically selected. Press Next.

Histogram In Chart Options, fill in the Title Category Value labels. Press Next.

Histogram Chart Locations indicates the destination of the chart. Press Next for the final product

Histogram

Final touches include removing the Series block and widening the bars. Right click on Series and Clear.

Histogram To widen the bars, right click on any bar and select Format Data Series

Histogram Then click the Options tab and set the Gap width to 0.

The End