What is Variable n n A variable is

What is Variable? n n A variable is any characteristics, number, or quantity that can be measured or counted. A variable may also be called a data item. Age, sex, business income and expenses, country of birth, capital expenditure, class grades, eye colour and vehicle type are examples of variables. It is called a variable because the value may vary between data units in a population, and may change in value over time. Chap 1 -1

Types of Variables Chap 1 -2

Types of Variables 1. Numeric variables: n have values that describe a measurable quantity as a number, like 'how many' or 'how much'. n are quantitative variables. n Numeric variables may be further described as either : a) Continuous variable any value obtained by measuring. Examples: height, time, age, temperature b) Discrete variable any value obtained by counting. Examples: number of cars, number of children, etc. n The data collected for a numeric variable are quantitative data. Chap 1 -3

Types of Variables 2. Categorical variables: n n have values that describe a 'quality' or 'characteristic' of a data unit, like 'what type' or 'which category‘ are qualitative variables and tend to be represented by a nonnumeric value. Categorical variables may be further described as : a) Ordinal variable any value can be ordered or ranked. Examples: GPA, clothing size (S, M, L), attitudes b) Nominal variable any value is not able to be organized in a logical sequence. Examples: sex, business type, religion, brand, etc. The data collected for a categorical variable are qualitative data. Chap 1 -4

Types of Variables n Quantitative and qualitative data can be gathered from the same data unit depending on whether the variable of interest is numerical or categorical. For example: Data unit A person Numeric variable Quantitative data Categorical variable Qualitative data "How many children do you have? " 4 children "In which country were your children born? " "How much do you earn? " $60, 000 p. a. "What is your occupation? " Photographer "How many hours do you work? " 38 hours per week "Do you work full-time or part-time? " A house "How many square metres is the house? " 200 square metres "In which city or town is the Brisbane house located? " A business "How many workers are currently employed? " 264 employees "What is the industry of the Retail business? " A farm "How many milk cows are located on 36 cows the farm? "What is the main activity of the farm? " Australia Full-time Dairy Chap 1 -5