1305AFE Lecture Notes - Lecture 1: Stratified Sampling, Statistical Inference, Australian Securities Exchange
Week 1 Business Data Analysis lecture notes
Introduction to Statistics and Sampling Methods
Part A: Intro to Statistics
What is statistics?
• Statistics is a body of principles and methods used to extract useful from a data set
to assist people to make decisions about questions of interest
• Data are actual observations that result from an investigation or an experiment or a
survey
• statistics is a ay to get iforatio fro data to ake ifored deisios
Who uses it?
• Statistical techniques are used extensively by marketing professionals, business
managers, quality control officers, hospital administrators, educators, accountants,
economists, politicians, physicians, etc.
Statistical terminology
• Population vs. Sample
• Population parameter vs. sample statistics
• Population:
o A population is the group of all or total items of interest to a statistics
practitioner
o Frequently very large (sometimes infinite)
▪ Examples
• The census accounts for the population or all the people
residing in Australia- over 23.64 million (finite)
• Number of fish in Brisbane river (infinite)
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find more resources at oneclass.com
• Sample:
o A sample is a set of data drawn from the population
o Smaller than the population
▪ Examples
• A sample of 100 people living in Australia
• Todays ath of a fishera i Brisae rier
Key Statistical concepts
Statistical terminology
• Population parameter
o A descriptive measure of a population
o Examples
▪ Average annual income of all Australians
▪ Proportion of defective shoes manufactured in a shoe factory
find more resources at oneclass.com
find more resources at oneclass.com
• Sample statistics
o A descriptive measure of a sample
o Examples:
▪ Average annual income of 100 randomly selected Australians
▪ Proportion of defective shoes in 200 randomly selected shoes
manufactured in a shoe factory
Why use a sample?
• A survey of the whole population is called a CENSUS (e.g. ABS Census)
• Why sample?
o Cost (cheaper)
o Time constraints (faster)
o Large population size- Census too
o Cumbersome (easy to handle)
o Destructive sampling- impractical (more practical)
o Accuracy of analysis (more accurate)
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Who uses it: statistical techniques are used extensively by marketing professionals, business managers, quality control officers, hospital administrators, educators, accountants, economists, politicians, physicians, etc. If we survey the students in this class today their height, we would be collecting cross sectional data: wide application for statistical analysis, example: australian unemployment rates at state level, 2016. Two basic areas of statistics: descriptive statistics, deals with methods of organizing, summarizing and presenting data in a convenient way. Is a body of methods for estimating and drawing conclusions about the population characteristics (population parameters) from a sample taken from the population. Methods of collecting data: published data (primary data vs. Survey methods: there are three types/methods to conduct surveys, personal interview, telephone interview, self-administered questionnaire, personal interview. In personal interviews, people are trained to ask prepared questions: advantages, having higher response rate, have fewer incorrect responses from respondents misunderstanding some questions, disadvantages, expensive- training interviews and travel expenses, personal bias, telephone interview.
