STATS

• Statistics


  (in singular sense) A branch of science that deals with the development of methods for a more effective way of collecting, organizing, presenting, analyzing, and interpreting data
• Statistics is an essential tool in education, government, office of justice programs, business and economics, medicine, experimental psychology, sociology, sports, actuarial work, criminology, employment figure, heredity, insurance, public opinion polling, census, and many other fields
• Statistics


  Aids in decision-making
• Descriptive Statistics


  Concerned with summarizing and describing important features of data collected, using tabular and graphical displays, without attempting to infer
• Inferential Statistics


  Concerned with making generalizations (inferences and predictions) about a large group of observations based on the data collected from a smaller group; requires statistical techniques
• Mrs. Planas forecasted to pay PhP 2,000 next month for her electricity bill based on her last year's bill
• Lebron James wants to know his average score for the past 7 games


  • DESCRIPTIVE STATISTICS
• Population


  Complete set of individuals, objects or measurements under study
• Sample


  A representative subset of a population
• Data


  Facts or information that are collected for reference and analysis, can be numeric or non-numeric
• Primary Data

  Data gathered are original
• Secondary Data


  Data that were previously gathered from an original source
• Variable


  A characteristic that may take on different values
• A group of researchers is interested in determining the number of children below 12 years old infected with COVID-19 in Caraga
• Population: Children below 12 years old in Caraga
• Variable of Interest: Whether or not the child has ever been infected with COVID-19
• A group of researchers is interested in determining the age of the patients infected with COVID-19 in MJ Santos Hospital
• Population: Patients infected with COVID-19 in MJ Santos Hospital
• Variable of Interest: Age of the COVID-19 patients in MJ Santos Hospital
• Quantitative Variables


  Variables that are measured on a numeric or quantitative scale
• Qualitative Variables


  Variables that are names or labels, thus can be categorized (categorical variables)
• Discrete Variables


  Variables with a finite or countable number of possible values
• Continuous Variables


  Variables that assumes any value in a given interval
• Quantitative Variables


  • Weight (in kgs), Foot length (in cm)
• Qualitative Variables


  • Address, Color of the Leaf, Brand of Cellphone
• Discrete Variables


  • House No., Number of Units Enrolled, SSS Number
• Continuous Variables


  • Weight (in kgs), Foot length (in cm)
• Statistics (in plural sense)


  Summary measures describing a specific characteristic of a sample
• Parameters


  Summary measures describing a specific characteristic of a population
• The Office of the Vice President for Academic Affairs wants to find out if there is a need to resume the full face-to-face classes. They interviewed 1,000 of the 5,000 enrolled students in the university to assess the readiness of the students for full face-to-face learning. The survey results showed that 7% of the 1,000 students are not yet ready for full face-to-face learning
• 7% - statistic
• Variable


  A characteristic which may take on different values
• Civil Status, Class Ranking, Temperature in oC, Height, Citizenship, Income, Sex, Age, Standardized Exam Score, IQ, Socioeconomic Status, Time of Day
• Nominal Level


  The data collected are labels, names or categories, frequencies or counts of observations belonging to the same category can be obtained, the lowest level of measurement
• Ordinal Level

  Data collected are labels with implied ordering, does not indicate the magnitude of the differences between measurements
• Interval Level


  The level of measurement that does not only indicate ordering but also the exact distance between the values of the measurement, the values for this kind of measurement lacks an absolute zero
• Ratio Level


  The same as interval level, however, the number zero indicates the absence of the characteristic being measured (has absolute zero)
• Civil Status, Citizenship - Nominal Level

  Class Ranking - Ordinal Level

  Temperature in oC, Standardized Exam Score, Time of Day - Interval Level

  Height, Income, Age - Ratio Level
• Data Collection


  The process of gathering and measuring information on variables of interest in an established systematic way that enables one to answer queries, stated research questions, test hypotheses, and evaluate outcomes
• Data Collection facilitates decision-making and improves the quality of decisions made