Aims The main aim of this section is to look at some different ways of measuring price increases.

In this section you will be looking at measuring price changes using price indices. In order to do this you will need to understand the concept of a price ratio. Price ratios are another way of looking at price increases or decreases, related to the proportional and percentage increases and decreases you have seen before.

Author(s): The Open University

A lot of people use the equals sign wrongly in places where another word or phrase might actually make the meaning clearer. Sometimes a link word or phrase is useful at the beginning of a mathematical sentence: examples include ‘So’, ‘This implies’ or ‘It follows that’ or ‘Hence’.

## Example 3

Author(s): The Open University

The interquartile range is a useful measure of dispersion in the data and it has the excellent property of not being too sensitive to outlying data values. (That is, it is a resistant measure.) However, like the median it does suffer from the disadvantage that its calculation involves sorting the data. This can be very time-consuming for large samples when a computer is not available to do the calculations. A measure that does not require sorting of the data and, as you will find in later uni
Author(s): The Open University

Everyone professes to understand what is meant by the term ‘average’, in that it should be representative of a group of objects. The objects may well be numbers from, say, a batch or sample of measurements, in which case the average should be a number which in some way characterises the batch as a whole. For example, the statement ‘a typical adult female in Britain is 160 cm tall’ would be understood by most people who heard it. Obviously not all adult females in Britain are the same
Author(s): The Open University

Histograms provide a quick way of looking at data sets, but they lose sight of individual observations and they tend to play down ‘intuitive feel’ for the magnitude of the numbers themselves. We may often want to summarize the data in numerical terms; for example, we could use a number to summarize the general level (or location) of the values and, perhaps, another number to indicate how spread out or dispersed they are. In this section you will learn about some numerical summaries
Author(s): The Open University

It is a fundamental principle in modern practical data analysis that all investigations should begin, wherever possible, with one or more suitable diagrams of the data. Such displays should certainly show overall patterns or trends, and should also be capable of isolating unexpected features that might otherwise be missed. The histogram is a commonly-used display, which is useful for identifying characteristics of a data set. To illustrate its use, we return to the data set on infants with SI
Author(s): The Open University

China - Economic Miracle or Economic Timebomb?
The growth of China in recent years has been described as an economic miracle with Western companies and governments rushing to build partnerships with the new power in the East. The opening up of the Chinese market and the expansion of industry, technology and production within the country has, however, had a profound effect on the people of China, its political leaders and the rest of the world. This impact can be seen in the growing inequalities within China, the loss of jobs in the west a
Author(s): No creator set

French Lesson - Dans la Ville (In the City), Part 9
Learn French by learning vocabulary words for buildings in the city. As the native French speaker recites the words, the words and the appropriate images appear. There is no English spoken. Each French phrase is spoken once. For beginning to intermediate learners. This video features a picture within the picture, so the viewer may want to open the video to 'full screen' to see the smaller image
Author(s): No creator set

Digital Library Object - Graphics-oriented battlefield tracking systems: U.S. Army and Air Force int
Author(s): No creator set

Studying mammals: The insect hunters
From pygmy shrews to armadillos, a wide range of mammals survive on a diet made up largely of insects. Many of these have fascinating adaptations suited to catching or rooting out their prey. In this free course, Studying mammals: The insect hunters, you will learn about these adaptations, along with survival strategies for when food is scarce. This is the second course in the Studying mammals series.Author(s): Creator not set

Studying mammals: Food for thought
Who were our ancestors? How are apes and humans related? And where does the extinct Homo erectus fit into the puzzle? In this free course, Studying mammals: Food for thought, we will examine culture, tool use and social structure in both apes and humans to gain an understanding of where we come from and why we behave as we do. This is the tenth course in the Studying mammals series.Author(s): Creator not set

Evolution through natural selection
In this free course, Evolution through natural selection, we describe the theory of evolution by natural selection as proposed by Charles Darwin in his book, first published in 1859, On the Origin of Species by Means of Natural Selection, or The Preservation of Favoured Races in the Struggle for Life. We will look at natural selection as Darwin did, taking inheritance for granted, but ignoring the mechanisms underlying it.Author(s): Creator not set

Animals at the extremes: The desert environment
Animal life has adapted to survive in the most unlikely and inhospitable habitats. This free course, Animals at the extremes: The desert environment, looks at the surprisingly diverse desert climates throughout the world and mammals, birds, lizards and amphibians that survive there. It splits these animals into three groups according to their strategy for survival: evaders, evaporators and endurers, then discusses how these strategies work on a biochemical and physiological level. Author(s): Creator not set

Water for life
Atoms, elements and molecules are the building blocks of everything that makes up our world, including ourselves. In this free course, Water for life, you will learn the basic chemistry of how these components work together, starting with a chemical compound we are all very familiar with water. First published on Wed, 17 Jan 2018 as Author(s): Creator not set

Studying mammals: Meat eaters
The powerful and majestic carnivores are the focus of many television documentaries. In this free course, Studying mammals: Meat eaters, we will delve into the lives of these fearsome hunters and explore their physical adaptations and social behaviour. This is the fifth course in the Studying mammals series. First published on Wed, 16 Mar 2016 as
Author(s): Creator not set

Studying mammals: Plant predators
From the mouse-deer to the elephant, plant eaters come in all shapes and sizes. But how do they manage to flourish on a salad diet? In this free course, Studying mammals: Plant predators, we will examine the special features that allow them to extract their nutrients from leaves, and see how some plants protect themselves from these predators. This is the fourth course in the Studying mammals series.Author(s): Creator not set

Studying mammals: A winning design
The term mammal encompasses a huge variety of animals, including humans. But what makes a mammal a mammal? This free course, Studying mammals: A winning design, explores some of the features, such as reproduction, lactation and thermoregulation methods, that mammals have in common. It is the first in a series of ten Studying mammals courses. First publ
Author(s): Creator not set

Studying mammals: Chisellers
Ever wondered why rats, mice and squirrels seem to reproduce at such an alarming rate? Rodents are among the most successful of all the mammal groups. In this free course, Studying mammals: Chisellers, you will learn more about some of the evolutionary features that make these creatures so plentiful. This is the third course in the Studying mammals series.
Author(s): Creator not set

This course explores the topic of climate change and global warming. We will begin by exploring how the Earth's global mean surface temperature is determined through a global “balancing act” of the rate of energy that comes from the Sun and the rate at which the planet returns that energy into space. We will also discuss the natural greenhouse effect, and how this contributes to a balanced global climate. We will then go on to consider the human impact on the atmosphere, including the imp
Author(s): The Open University

This course will allow you to extend your visual modelling skills through the use of the sign graph diagramming technique. You will explore the dynamic relationship between social, economic and ecological factors whose interdependencies will determine the complex dynamics of the future as it unfolds. Your final task will be to identify points of intervention within this complex system in order to "nudge" the situation towards a more favourable outcome.

This OpenLearn course provides a s
Author(s): The Open University