2. Mathematics Essential to be precise Normal, usual. Normal has several mathematical meanings. Use usual for the non-mathematical meaning Avoid definite, strict, proper, all, some Intractable – true meaning if the problem is NP- hard Formula, equation – formula is not an equation. An equation has an equality

3. Mathematics Equivalent, similar – equivalent means undistinguishable, similar – close Element, partition – element is a member of set and not used to mean as part of a subpart of an expression. Partition – used to create subsets Average and mean – use arithmetic mean or mean. Average means typical

4. Mathematics Follow the rules of readability Use () of appropriate size Sentences with embedded mathematics should be structured as if each formula was a simple phrase Give the type of variable each time use, list L Displayed formulas should be positive results, so readers will be not be mislead Same font size

5. Numbers Numbers should be usually written as figures, not spelt out. Exceptions: –approximate numbers, –numbers up to twenty unless they are literal values or part of an expression –numbers at the start of sentence –Percentages should always be in figures

6. Numbers Don’t mix modes –There were between four and 32 processors in each machine. –There were between 4 and 32 processors in each machine Numbers never adjacent –There were 14 512 Kb sets. –There were fourteen 512 Kb sets. Never omit the 0 in numbers less than 1 Use same accuracy Be careful with percentages, explicitly state

7. Presentation of Statistics Text paragraph semitabular form tables graphics

8. Text Presentation Most common when only a few statistics. Writer can direct the reader’s attention to certain numbers or comparisons drawback - statistics are submerged in the text A comparison of the four top revenue producing computer software companies from the Fortune 500 survey show that Compuware had the largest % change in revenue from the years 1998-1999. Its growth was 44%. This compares to revenue growth of Microsoft at 36%, Oracle at 24% and in fourth was Computer Associates Intl. at 11%.

9. Semitabular Presentation Just a few figures, figures my be taken form the text and listed. Quantitative comparisons are easier to read in a list

10. A comparison of the four top revenue producing computer software companies from the Fortune 500 survey show that Compuware had the largest % change in revenue from the years 1998-1999. $ millions % Change From 1998 Microsoft 19,747 36 Oracle 8,827 24 Computer Assoc. Intl. 5,253 11 Compuware 1,638 44 Semitabular Presentation Example

11. Tabular Presentation Superior to text in presenting statistics should be accompanied by comments directing the reader’s attention to important figures either general or summary general tend to be large, complex, detailed and left for the appendix

12. Tabular Presentation Summary tables contain only a few key pieces of data closely related to the finding to make them inviting to the reader, the table designer should omit unimportant details and collapse multiple classifications into composite measures contain enough information for the reader to understand its contents

13. Tabular Presentation Title should explain the subject, how the data are classified, the time period if the data does not come from your original research, there should be a source note

14. Diagrams Are used to show process, structure or state Browse relevant papers to show what elements to incorporate and how it should be presented

15. Graphs Compared with tables, graphs show less information and often only approximate values they are more often read and remembered than tables many different graphic forms boxplots, stem-and-leaf displays, histograms, line, area, pie, bar, pictographs and 3-D graphics

16. Graphs Each one should be numbered for easy reference descriptive caption always introduced and discussed within the text if not your own, can only be reused with permission of the author and the publisher of the original

17. Graphs Support the evidence for the hypothesis keep simple few plotted lines

18. Spreadsheet Software Allows the user to take control of numbers, manipulating them in ways that would be difficult or impossible otherwise graphs - were once very difficult, now part of the software can turn the worksheet numbers into charts automatically

19. Creating Charts from Numbers Offer a variety of basic chart types and options for embellishing charts differences among chart types are more that aesthetic each chart type is well suited for communicating particular types of information

20. column bar Stacked bar Spider or radar pie Multiple pie line bubble area doughnut scatter

21. Pie Chart Relative proportions of the parts to a whole used with nominal data Multiple pie – same as pie but displays another data series

22. Line Chart Show trends or relationships over time show relative distribution of one variable through another (the classic bell-shaped normal curve)

23. Example of Line Chart

24. Bar Charts/Histograms Appropriate when data falls into a few categories. Bars can be stacked in a stack chart that shows how proportions of a whole change over time. Conventional solution for the display of interval-ratio data Note that it shows order to its categories

25. Example of a Bar Chart

26. Scatter Charts Used to discover, rather that display a relationship between two variables

27. Example of a Scatter Chart (Graduation Rate vs Crime Rate)

28. Others Bubble – used to introduce third variable (dots of different sizes) Axis could be sales and profits; bubbles are assets Spider, radar – radiating arms are categories; values are distances form centers (shows multiple variables e.g. performance, ratings, progress)

29. What about graphs and charts? 1992 Presidential election - ( Ross Perot used many graphs) One picture is worth a thousand words Candidates spoke about trend lines, investments and deficits and did so using colorful charts and graphs. voodoo economics

30. What about graphs and charts? It is simple to create a line graph that drives home the increase in the national debt, a bar graph that compares market share for U.S. and foreign automobile manufacturers. When you design a graph you have a responsibility to your audience

31. The “real” Trend

32. Different Axis Calibration

33. Guidelines Choose the right chart for the job. Keep it simple, familiar and understandable Strive to reveal the truth, not hide it.

34. Spreadsheet Ethics: Making Numbers Lie Figures do not lie …but, you must be careful about the figures you see, for they are only as accurate as the person who entered them.