Learning outcomes After finishing this unit you should be able to: use the Windows calculator to carry out basic operations and calculate percentages; interpret and use information presented in tables and charts; be able to round numbers appropriately.
9.1 Further reading
*The Good Study Guide by Andrew Northedge, published by The Open University, 1990, ISBN 0 7492 00448. Chapter 4 is entitled ‘Working with numbers’ Other chapters are entitled: ‘Reading and note taking’, ‘Other ways of studying’, ‘What is good writing?’, ‘How to write essays’, ‘Preparing for examinations’.
The Sciences Good Study Guide by Andrew Northedge, Jeff Thomas, Andrew Lane, Alice
7.2 Averages The mean, median and mode are all types of average and are typical of the data they represent. Each has advantages and disadvantages, and can be used in different situations, but they all give us an idea of the general size of the values involved. Here we provide brief definitions, and some idea of when each should be used. The following set of data i 7.1 Introduction Charts, graphs and tables are all very helpful ways of representing a set of data. However, they are not the only ways of passing on information about data. This section looks at how you can analyse a set of data to summarise the given information as briefly and simply as possible. Essentially, there are two features of a set of data that enable summarising: the average and the spread. This section starts by looking at what is meant by ‘average’. If you have already studied OpenL 6.1 What is a pie chart? A pie chart is a circular chart (pie-shaped); it is split into segments to show percentages or the relative contributions of categories of data. A pie chart gives an immediate visual idea of the relative sizes of the shares of a whole. It is a good method of representation if you wish to compare a part of a group with the whole group. You could us 5.3 Histograms The simplest definition of a histogram is that it is a bar chart with the adjacent bars touching each other. Unlike a bar chart, histograms are usually drawn only with vertical bars. Generally, histograms are used to illustrate continuous data whereas bar charts are used to illustrate discrete data (distinct categories). 5.2.2 Continuous variables Not all numbers are discrete. Consider the following measurements: times to run a marathon temperatures recorded at intervals during a day weight of each bunch of grapes sold at a supermarket yesterday. Time, temperature and weight are all examples of numerical data, but there is not a restricted set of values that they can take. Whereas you can have 2 or 3 children in a family but not 2.5, with tempe 5.2 Discrete and continuous variables You may have been wondering why bar charts are generally drawn with separate bars. There is a reason for this and to discover what it is, you need to look at the nature of the categories of data being used. 4.8.3 Mode The mode, or modal value, is the most popular value in a set of numbers, the one that occurs most often. However, it is not always possible to give the mode as some sets of values do not have a single value that occurs more than each of the others. Like the median, the mode can help us to get a better feel for the set of values. Retailers find the mode useful when they want to know which item to restock first. 4.5 Histograms Histograms are a special form of bar chart in which the bars usually touch each other because histograms always show data collected into ‘groups’ along a continuous scale. They tend to be used when it's hard to see patterns in data, for example when there are only a few variables, or the actual amounts are spread over a wide range. For example, suppose you manufactured biscuits; it is important to manufacture closely to a given size, as there are regulations governing the sales of biscuit 4.3 Pie charts, bar charts, histograms and line graphs These are all different ways of representing data and you are likely to be familiar with some, if not all of them. They usually provide a quick summary that gives you a visual image of the data being presented. Below, we have given a brief definition and some ideas of how each can be used, along with a corresponding activity. We suggest that you look out for similar examples in everyday life, and question the information that you see. 4.1 Reading data from tables Tables are used as a way of describing what you are talking about in a structured format. They tend to be used to present figures, either as a summary or as a starting point for discussion. Tables are also probably the most common way of presenting data in educational courses. Tables have always been compiled by someone. In doing so, the compiler may have selected data and they will have chosen a particular format, either of which may influence the reader. You need to be aware of the co 3 Reading articles for mathematical information We gain much of our mathematical information from our surroundings, including reading newspaper and magazine articles. A skill that will be useful to all of us in our studies is the ability to do this in a structured way, as it is very easy to be uncritical of the information that we see. Newspapers and magazines frequently place mathematical information in the form of graphs and diagrams. All too often, we tend to assume that the information is correct, without questioning possible bias or i 7.1 Introduction If you want to improve your computing skills or knowledge, there are plenty of resources available to help you. This section aims to get your search started by providing you with some useful websites. 2.6 Back it up It's a good idea to get into the habit of regularly backing up your work files – things like your notes and assignments. This involves making a copy onto another storage device such as a floppy disk, CD-ROM or memory stick. If anything goes wrong with the hard disk on your computer and you lose all your data, it's some compensation to find that you have a recent copy of your files. To avoid losing important system files that run your computer, back them up using a data storage system 2.5 Find out how computers work The BBC offers an Absolute Beginners' Guide to Using Your Computer (accessed 8 November 2006). This guide is ideal for anyone really new to computers. If you're interested in the more technical aspects of how computers work and how they've developed over time, have a look at the BBC/Open University Information Communication Technology portal (accessed 8 November 2006). 2.4 See what you can do on the web The web is immense, made up of information held on computers across the world. You can find out things about any subject or topic you care to name, however obscure it might be. The section entitled Searching later in this unit provides advice and tips on searching the web and finding what you want. 2.3 Learning more Consider your main use for the PC, and check that you have the skills or knowledge you need. Although some students use spreadsheets and databases, the key skills for most students are: word processing study notes and assignments; searching for information on the web; using conferencing and email. If you feel you need to know more about using your computer there are a number of options open to you. 2.2 Before your course starts Allow some time to get yourself ready for a course that involves using a PC. If you already have a PC: double check it against the PC specification for your course. don't assume that a lower specification will be sufficient. If your computer doesn't meet the specification, you might: be able to upgrade it. Check with the institution you're studying with. They should have 1.1 Ways in which computers can help you to study Courses use computers for a variety of different reasons. These are a few examples. To let you explore ideas and concepts in more depth, such as by using a multimedia CD-ROM or DVD with interactive exercises. To help you communicate with others on your course. Online conferences offer a way to contact other students and staff for information, discussion and mutual support. To allow you to analyse data, see pictures or
7.2.1 Mean, median and mode
6.1.1 When are pie charts used?
5.3.1 What is a histogram?
