Statistics & probability

• Statistics is the science of collecting, classifying, organizing, summarizing, analyzing, and interpreting data to draw conclusions or make decisions
• Descriptive statistics uses numerical and graphical methods to reveal patterns in a data set and present information conveniently
• Inferential statistics generalizes results or draws conclusions from a sample to the population and measures their reliability
• Data consists of information obtained from observation, counts, measurements, or responses
• Census is the collection of data from every element in a population
• Unit is the individual object or person in the population, often called subjects
• Variable is the characteristic of interest to be measured for each unit in a sample
• Population is everything under consideration or a complete set of items of interest in the research
• Sample is a subset of the population
• Parameter is a numerical description of a population characteristic
• Statistic is a numerical description of a sample characteristic
• Types of Data:

  Quantitative Data consist of numbers representing counts or measurements
• Discrete data result when the number of possible values is a finite or countable number
• Continuous data results from infinite values corresponding to a continuous scale
• Qualitative Data have different categories distinguished by nonnumeric characteristics
• Common ways of collecting data:

  <|>Previous information from newspapers, magazines, the World Wide Web, annual reports, etc.
• Observation obtained from direct observation, measurement, and counting
• Experiment obtained the required information through actual and real experiments
• Interview obtained through asking questions directly from respondents through household surveys, street surveys, or telephone interviews
• Questionnaires obtained data through a set of questionnaires from respondents to answer