Why use Statistics? Discuss. 22nd February 2005 Why use Statistics? Discuss.

Statistics 22nd February 2005 Objective: To understand the use and application of statistics and identify different types of data. Statistics is used when you want to make sense of large amounts of data or information. However, when collecting and interpreting data, it is important to understand how reliable the data is.

Statistics 22nd February 2005 For example: “Four in ten criminal offenders in the USA report alcohol as a factor in violence.” “47% of people in Great Britain supported the ban on fox hunting with dogs” (2, 234 people interviewed, Mori Survey) Question: What are the possible problems with such statements? Do the facts represents the view of all people? Discuss.

Statistics Types of Data: 22nd February 2005 We need to observe or measure things to get data. This observation is called a variable. Types of Data: Quantitative variables: Qualitative variables: These have numerical observations, such as shoe size (7, 8, 9, 7.5, 8.5) Height (178cm, 1.9m) and weight. Variables that have non-numerical observations, eg. Eye colour, Favourite food

Statistics 22nd February 2005 Quantitative variables can be broken down further. Quantitative variables: Continuous data Discrete data …Are measured on a scale and can take any value eg. height The units of measurement (eg. CDs) cannot be split up; there is nothing between 1 CD and 2 CDs.

Statistics 22nd February 2005 Decide whether or not the following are continuous or discrete: Discrete because can only take specific values, eg, 7, 8, 8.5. Cannot get a size 8.35 a) Shoe size: b) Gender: Discrete because can only be male or female. c) The numbers of chocolates in a box: Discrete. d) Times taken for athletes to run 100m: Time is continuous

Discrete and continuous data Which data is discrete and which is continuous? the number of pages in a book the amount of money in a piggy bank the men's 100m sprint record time the number of Smarties in a tube the capacity of a car's petrol tank the length of your shoe the number of hairs on your head your age the temperature in Bulwell your shoe size Answers discrete continuous