Data analysis & visualisation Term 2 – Week 9 VCE IT – UNIT 2

Key knowledge On completion of this unit the student should be able to apply the problem-solving methodology and use appropriate software tools to create data visualisations that meet users' needs. – 1) stages of the problem-solving methodology – 2) types of information problems and users' needs that can be met through presenting information in visual forms – 3) problem-solving activities related to analysing information problems – 4) types of data visualisations – 5) sources of authentic data – 6) data types and data structures relevant to selected software tools (data structures include: arrays (in programming), tables, records and fields (databases), tables, worksheets (spreadsheets) – 7) purposes of data visualisations – 8) suitability of different types of visualisations that meet users' needs – 9) design tools for representing data visualisations – 10) needs of users that can influence the type and presentation of visualisations – 11) criteria and techniques for evaluating visualisations – 12) characteristics of file formats and their ability to be converted to other formats – 13) functions of appropriate software tools to select required data and to manipulate data when developing visualisations – 14) formats and conventions applied to visualisations in order to improve their effectiveness for intended users.

Key skills analyse information problems select appropriate sources of data and identify relevant data determine the suitability of different data types and structures for creating visualisations select types of visualisations that are appropriate to the data select and apply appropriate tools to represent the design of the visualisations apply software functions to locate and acquire data that will be input and manipulated use appropriate software tools, and select and apply a range of suitable functions to efficiently develop different types of effective data visualisations select appropriate techniques and apply criteria to determine the extent to which data visualisations meet users' needs.

Data typeDescriptionExample IntegerA whole number (no fractional part) , 394 Floating point numberA number with a fractional part , CharacterA single character of textE, $, 1, + (the '1' is stored as text and cannot be used arithmetically) StringAny number of text charactersstring45+&_44" NumberAny type of numeric storage (byte, integer, short/long floating point, currency etc) 12, -13.5, DateStores a day, month and year combination for any day in history. It's stored in a special format that lets software interpret the date and do comparisons and calculations with it 05/12/2010 Date + 3 = 3 days after Date. Date2-Date1 gives the number of days between date1 and date2. 12 March 2011 Logic (Boolean)Stores a single value - true or false. Boolean takes very little memory and storage space. IsMarried = TRUE If IsMarried = FALSE Then Happy = TRUE

Problem solving methodology

Presenting information in a visual form Many people prefer information to be presented in a visual form rather than lines of text or figures. Used correctly, data visualisation can increase the clarity and usability of information, therefore increasing its effectiveness.

Presenting a data visualisation solution Users or clients may be looking for a data visualisation solution when they are looking for clarity or to identify patterns or relationships from a data set. If the user is looking to: – Compare data, a bar chart might be used – Show a distribution of data, a histogram might be used – Show a relationship between two data sets, a scatter diagram might be used – Show a comparison of data that changes over time, this might involve an animation or simulation

Often before we start this process, we have an idea of what the solution might roughly look like based on the needs of the users. We might ask the following questions: – Does the information problem involve data analysis? – Does the data need to be compared? – Does a distribution need to be identified from the data set? – Does a relationship between two sets of data need to be identified? – Does the user need to make a decision from a collection of data? – Is there a need for the data to be communicated in a graphical way because of the types of users?

Analysing information problems If you get the analysis stage of the PSM correct, your solution is more likely to be successful as you have a clear understanding of the problem. Analysis stage often involves the process of determining the scope, requirements and constraints of a solution. It involves an investigation of the factors that affect the problem (constraints), identification of the need of the users (requirements), and the output that must be produced to meet those needs (scope). A common technique is to write the problem out as a short statement or question.

Refer to the ‘Southside Makers’ case study (p.180 of your text book).

Obtaining feedback When seeking feedback, there are two types of data, quantitative and qualitative. – Quantitative: measurable and specific and therefore easier to chart or graph. At a simplistic level, quantitative data gathering is based on verifying theory through the use of statistics and largely numerical data. For example, ’50% of people bought a product from the market’. Can be gathered by using surveys, questionnaires or observation. Data can then be analysed with the use of programs such as Excel. This takes time and often involved hours of data entry. Easy to communicate using data visualisations, such as pie charts.

– Qualitative data is harder to measure. Can be gathered via the following instruments: interviews, video footage and observation. These need to be recorded accurately and are generally transcribed later. More descriptive than quantitative data. Analysis is different to that of quantitative. Researcher needs to establish rich descriptions and find themes through classification and coding. Text clouds can be used to analyse qualitative data.

Data visualisation can be used as part of the information solution, as well as at the analysis stage to identify further data that might be needed to properly scope the problem before moving on to the design phase.

Activity Use to create text clouds and identify the most common words in: – The valedictorian file from Wiki – The inspirational quotes from /inspirational.htm /inspirational.htm – Martin Luther King’s speech – George Bush’s response to September 11 – Obama’s speech after the Japanese earthquake – Your favourite song

Defining the problem Based on situation given, you need to be able to identify the problem. From there, you then need to be able to develop a solution.

Solution requirements Imagining the solution before it has been produced takes a lot of thought. How is the organisation going to use the information? In what format does it need to be presented?

Constraints A constraint is any factor that influences the nature of the solution, the style and size of the solution or the characteristics of the users. It is important to try and identify as many constraints as possible before heading into the design phase of the PSM, such as: – Does the solution need to appeal to a certain gender? – Does the solution need to appeal to a certain learning style? – If the resulting solution is a data visualisation, is the audience familiar with the problem or will they be seeing this solution for the first time? – How much detail does the solution need to have?

Limitations need to be considered. Will there be any variables that will limit the usability of the solution, such as: – Does the solution have technical limitations? – Can the solution only be viewed by a certain piece of software or by a certain browser? – Do you need to register or have an account to access the solution? – Is the solution time-sensitive? Does it have to be communicated within a specific time range? – Are there aesthetic limitations that prevent visually- impaired users accessing the information? Limitations