1.2.1 Rounding to the nearest hundred You will probably think to yourself that the coat shown costs about £300. £290 is considerably closer to £300 than it is to £200, so £300 is a reasonable approximation. In this case, 290 has been rounded up to 300. Similarly, 208 would be rounded down to 200 because it is closer to 200 than it is to 300. Both numbers have been rounded to the nearest hundred pounds. When rounding to the nearest hundred, anything below fifty rounds down. So 248 rounds to 200. Anything o
1.3.3 The median The median is essentially the middle value of a batch when the values are placed in size order; it is found in the following way. First, all the values in the batch are sorted into ascending order; that is, smallest first, then second smallest, and so on, ending with the largest. Then, see if the batch size is odd or even. If there is an odd number of values in the batch, then the middle value in the list is the median. If there is an
7 OpenMark quiz Hopefully, thinking about how your solution to a mathematical problem might be marked, will help you to produce better solutions for yourself, as well as for somebody else. Now try the quiz and see if there are any areas you need to work on.
3.2.1 Try some yourself 1 You are planning to paint three rooms with total wall areas of 56, 38 and 40 square metres, using paint that comes in tins which claim to cover 15 square metres per tin. How many tins will you need for each room? And how many in total? 1.1 Writing mathematics How do you write mathematics that can be read and easily understood by anyone else, such as a tutor or another student? It takes practice, but the following guidelines may be helpful. Ensure that what you write consists of sentences. Too many people believe that mathematics is a language which is entirely made up of unfamiliar symbols. It is not. Many symbols act in part merely as abbreviations which, when read, can be translated back into spoke 8 Get some practice Now that you’ve learned how to do subtraction on paper, you might want to practice your new skills. To practice subtracting whole numbers, including borrowing where necessary, go to the Practice Subtracting section of the Numbers website and click on Get sum. Then follow the instructions. 7 Dividing when you have to carry If the number you are dividing by does not go exactly (with no remainder) into the digit you are dividing into, you need to do something called carrying. Say you want to divide 952 by 7. The process is basically the same as in the previous section. First write it down on paper. Then, to do the calculation, you take each digit from the number being divided in turn, starting with the one on the far left, and see how many times the dividing number, 7 in this case, goes into it. The calcul 1.2.1 Data sets in different tabular forms In much of your statistical work, you will begin with data set, often presented in the form of a table, and use the information in the table to produce diagrams and/or summary statistics that help in the interpretation of the data set. However, in practice, much interpretation of data sets can be done directly from an appropriate table of data, or by re-presenting the data in a rather different tabular form. Dealing with data in tables is the subject of this section and the next. By the time 1.1.3 Comparing data sets using boxplots Boxplots are particularly useful for making quick comparisons. The following example relates to birth weights of infants exhibiting severe idiopathic respiratory distress syndrome (SIRDS), and the question ‘Is it possible to relate the chances of eventua Acknowledgements All materials included in this unit are derived from content originated at the Open University. Except for third party materials and otherwise stated (see terms and conditions), this content is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Licence 1.2.7 Problems with graphics: USA workforce The danger of using three-dimensional effects is really brought home when two data sets are displayed on the same bar chart. Table 2 may be thought of as consisting of two data sets, one for male workers and one for female workers. On its own, each of these data sets could be portraye 4 Your formulas – using a spreadsheet Although there may be many occasions when you are given a formula to use, sometimes you may need to devise your own formulas, for example if you use a spreadsheet on a computer at home or at work. This section looks at the process of devising a formula in more detail. Part of a spreadsheet that has been constructed to record monthly income and expenditure is shown below. It is similar to a balance sheet that you might draw up by hand and includes the monthly income and outgoings, the to Acknowledgements All written material contained within this unit originated at the Open University. 3.4.1 Try some yourself 1 A new train operator boasts ‘Train times reduced by 12%’. Decrease 90 minutes by 12%. Give your answer as minutes and seconds. A 12% decrease would red 2.6 Division of complex numbers The second of the conjugate–modulus properties enables us to find reciprocals of complex numbers and to divide one complex number by another, as shown in the next example. As for real numbers, we cannot find a reciprocal of zero, nor divide any complex number by zero. 2.3.4 Klein bottle There are two other surfaces that can be obtained by identifying both pairs of opposite edges of a rectangle. In one of these, shown in Figure 31, we first identify the edges AB and A'B', labelled a, in the direction shown by the arrowheads. This gives us a cylinder, as before. We then try to ident Episode 96 - Windows Azure Store | Windows Azure Cloud Cover Show In this episode Nick, Chris and Nate are joined by Bilal Aslam, Senior Program Manager on Windows Azure – who shows us the Windows Azure Store and how developers can both consume services available within the store and how developers can build content to be sold within the store. This week in the News: Lesson 07 - One Minute Luxembourgish Topic 7: Public Goods and Externalities Part 3 | Econ2450A: Public Economics Part 7: Data Binding and the SampleDataSource.cs | Windows Store apps for Absolute Beginners with C In this lesson, we begin the process of understanding how to utilize data in our app. We begin by looking at this from the GroupedItemsPage.xaml's perspective, and how it utilizes the CollectionViewSource to bind to a View Model provided in the LayoutAwarePage.cs. We talk about the DefaultViewModel object which implements IObservableMap<K, V> and what that really means. Finally, we pick apart the SampleDataSource.cs and observe it's inheritance hierarchy and the purpos
Example 1.2 Infants with SIRDS: boxplots
Answer
Example 2
In lesson 07 of One Minute Luxembourgish you will learn to say that it's nice to meet someone in Luxembourgish. Remember - even a few phrases of a language can help you make friends and enjoy travel more. Find out more about One Minute Languages at our website - http://www.oneminutelanguages.com. One Minute Luxembourgish is brought to you by the Radio Lingua Network and is ©Copyright 2008.
Raj Chetty
Fall 2012
