Statistics

• Statistics is a branch of mathematics, which deals with collection, organization, presentation, analysis, and interpretation of data.
• Use of statistics in ancient times

  1. Provide information pertaining to taxes

  2. Soldiers

  3. Agricultural crops

  4. Athletic endeavors
• Statistics


  Developed into an inferential science sometimes in the sixteenth century
• Statistics


  Largely developed on the theory of probability
• Statistics continued to develop as a result of the diligent research made by people in various fields during the past 400 years
• De Moivre (1733) - discovered the equation for the normal distribution upon which many of the theories of inferential statistics have been based.
• Adolf Quitelet (1796-1874) - Belgian. Statistics in field of psychology.
• Sir Francis Galton (1822-1911) - Statistics to social sciences. Heredity, Eugenics and Discoveries of percentiles.
• Karl Pearson (1857-1936) - Helped Galton to develop the theory of regression and correlation. Theories of sampling.
• William S. Gosset - developed methods for decision making.
• Sir Ronald Fisher (1890-1962) - statistics for experimental designs.
• *The study of statistics is considered to be very important because we frequently organize and express data numerically.
• *Everyday, we encounter statistics from weather forecast, election results, surveys, population census, grade in school, and understanding data regarding medical conditions of people in a certain place.
• *statistics can greatly affect our decisions in life.
• *in this times where fake news is rampant, learning statistics will be our guiding tool in determining which data shown by the media is factual or not. Our knowledge in statistics will help us process more effectively information, thus leading us to make the best decision in different situations.
• Data - are individual pieces of factual information recorded and used for the purpose of analysis. Raw information from which statistics are created. Refers to a systematic record of a specific quantity. Are the facts and figures that are collected, analyzed, and summarized for presentation and interpretation. It is the information we gather about the sample or the population. Measurements or observation that are collected as a source of information.
• Collection of Data - refers to the process of gathering data or information.
• Methods of Data collection:

  1. Surveys

  * Interview - it is a direct method of gathering data because this is done when a person requires a face-to-face inquiry from another person.

  *Questionnaire - an indirect method of gathering data because this makes use of questionnaires to be answered by respondents. This is used when the interview method is difficult to use.

  2. Observation of outcome of events - This method makes use of the different human senses in gathering information. its more about probability.
• Experiment - activity involving chance.

  Each repetition or observation of an experiment is a trial, and each possible result is an outcome.

  The sample space of an experiment is the set of all possible outcomes.
• 3. Experiment-is usually conducted in laboratories where specimens ore subject to be some aspects of control to find out cause and effects relationships.
• 4. Publication-This is where secondary data are gathered, like newspapers, journals, books, encyclopedia, magazines, or thesis of other researchers, etc.
• *organization of data-refers to the summarizing data into tables.
• Frequency-the number of times an event or observation happened in an experiment or study.
• *Presentation of data-presenting data through graphs or chart.

  Types:

  *pie chart

  *histogram

  *bar graph

  *line graph

  *pictograph
• *Analyzing data - describing the data using statistical methods and procedures.
• Interpretation of data- process af drawing conclusions based on the analyzed data.
• Two major Areas of statistics

  1. Descriptive statistics-defined as the collection, presentation, and description of sample data.
  2. Inferential statistics-making decisions and drawing conclusions about populations.
• Application of Statistics

  • Education
  • Government
  • Medicine and Physical Sciences
  • Psychology
  • Sociology
  • Business
  • Sports
• Education


  Statistical tools are used to get the information on enrolment, finance facilities, grading systems, etc.
• Government


  Data are gathered to guide the officials in managing the affairs of the state
• Medicine and Physical Sciences


  Methods of statistical designs of experiments are significant. The causes and effects of factors which affect experiments are best evaluated using statistical tools
• Psychology


  Psychologists are able to understand human behavior better if they are able to gather and interpret data on different tests
• Sociology


  Statistics is used in the study of the conditions of the society. In order to improve a society, different observations must be done, and with proper analysis and interpretation, it may result to a positive action that will benefit the people
• Business


  Statistics plays an important role in the financial transactions and marketing of new products, forecasting of business trends, controlling the quality of goods produced
• Sports


  Statistics are taken and recorded. These records help to keep track of succeeding performances for comparison
• Statistical Terms

  1. Population-as used in statistics, refers to a complete set of individuals, objects, places, or events under study.
  2. Sample-is defined as a subset of a population or a collection of some elements in a population.
  3. Census-is an official count or survey of a population, typically recording various details of individuals.
• • DATA is the information we gather about the sample or the population.

  Data may be classified into two major types

  1. Qualitative data-refers to the attributes or characteristics of the samples.
  2. Quantitative data- refers to the numerical information gathered about the samples. It can be subjected to the arithmetic operations.
• Two (2) types of Quantitative Data

  1. Discrete data-are values of the variables obtained through the process of counting. It can only have specific values.
  2. Continuous data-are values of the variables obtained through the process of measuring or weighing. It can take on any value in an interval.
• Levels of Measurement

  • Nominal Variable
  • Ordinal Variable
  • Interval
  • Ratio
• Nominal Variable


  A qualitative variable that categorizes, describes, or names an element of a population