Theory revision 2

• population
• it is a collection of possible individuals, objects or measurement of interest
• example: population of Australia.
• sample
• it is a portion or part of the population of interest
• example: 30 of UTS students
• parameter
• it is a measurable characteristic of a population
• example: total population of Melbourne
• statistic
• it is a measurable characteristic of a sample.
• example: 15 of wine lovers
• statistical inference
• it is the process of drawing conclusion from data subject to random variation such as observational errors and sample variation.
• example: 15 percent of beer lovers

Theory revision 1

• Statistic is the science of collecting, organizing, presenting, analyzing and interpreting numerical data to assist in making more effective decision. This technique is used extensively by marketing, accounting, quality control, consumers, professional sports people, hospital administrators , educators, politician and so on,
• Descriptive statistics is the methods of organizing, summarizing and presenting data in an informative way.
• Inferential statistics is a decision, estimate, prediction or generalization about a population, based on sample.
• Qualitative data is the characteristic or variable being studied is non numeric.
• Quantitative data is the variable that can be reported numerically.
• A population is a collection of possible individuals, objects or measurement of interest.
• A sample is a portion or part of the population of the interest.

Homoscedasticity

In statistics, a sequence or a vector of random variables is homoscedastic, if all random variables in the sequence or vector have the same finite variance.