Descriptive Statistics * Descriptive statistics deals with methods of organizing, summarizing, and presenting data in a convenient and informative way. * Graphical techniques is a form of descriptive statistics * Practitioners use graphical techniques to present data for readers to extract information in an easy way. * Numerical techniques is another form of descriptive statistics * Numerical techniques summarise data, e.g. measure of central location (mean/average), a measure of variability (range) etc.
Inferential Statistics * Inferential statistics is a body of methods used to draw conclusions or inferences about characteristics of population based on sample data. * An example of inferential statistics would be interviewing a sample size and infer from the data to estimate the desired result. This is used because collecting data from the whole population would be time consuming and costly.
1.1 Key Statistical Concepts
* A population is the group of all items of interest to a statistics practitioner. * Frequently very large and may be infinitely large. * Does not only apply to human population, can be the population of diameters of ball bearings produced at a large plant. * Parameter is a descriptive measure of a population. * In most applications of inferential statistics, the parameter represents the information needed.
Sample * A sample is a set of data drawn from the