Ethics

• Statistics refers to the collection of methods for planning experiments, obtaining data, and then analyzing, interpreting and drawing conclusions based on the data
• The term "statistics" came from the Latin phrase "ratio status" which means study of practical politics or the statesman’s art
• In the middle of the 18th century, the term "statistik" was used, defined as "the political science of several countries"
• Statistics is a scientific discipline consisting of theory and methods for processing numerical information that one can use when making decisions in the face of uncertainty
• Universe: collection of observational units under consideration
• Population: the set of all possible values of the variable
• Parameter: a descriptive measure of the population
• Sample: a subset of the population
• Statistic: a descriptive measure of the sample
• Aims of Statistics: to uncover structure in data to explain variation descriptively and inferentially
• Correct statistical process leads to correct, valid, reliable information
• Published data, survey results, and research output are sources of information used in statistics
• Everyday we use news and information sources to gather facts needed in making decisions
• Statistics is essential in various fields like agriculture, economics, health, physical science, and education
• Statistics aims to uncover structure in data to explain variation descriptively and inferentially
• Inferential Statistics - methods with the analysis of a subset of data leading to predictions or inferences about the entire set of data
• Variables vs. Data:

  • A variable is something whose value can vary and is a characteristic being measured
  • Examples of variables include age, sex, and blood type
  • A data value is the "realization" obtained upon measurement
  • Examples of data values are 54 years, female, and blood type A
• Types of Variables:

  • Qualitative variables describe characteristics
  • Quantitative variables represent amounts
  • Discrete variables can assume a finite number of values
  • Continuous variables can assume an infinite number of values within an interval
• Exercise:

  • Sex is a qualitative variable
  • Age is a quantitative variable
  • Height is a quantitative variable
  • Types of Location (urban, rural) is a qualitative variable
  • Academic Grade is a qualitative variable
  • Level of Pain (low, moderate, high) is a qualitative variable
• Level of Measurements:

  • Nominal scale has no order or distance
  • Ordinal scale has order but no distance
  • Interval scale has order and distance but no unique origin
  • Ratio scale has order, distance, and a unique origin
• Research Variables:

  • Factors, parameters, attributes, or qualities being measured or recorded
  • Examples include sex, age, height, weight, and color
  • Variables can be independent and dependent
  • Independent variable is changed or controlled by the experimenter and has a direct effect on the dependent variable
  • Dependent variable is being tested and measured in an experiment, dependent on the independent variable
• Other Names for Independent and Dependent Variables:

  • Independent variable is also known as exposure, explanatory, or manipulated variable
  • Dependent variable is also known as control, outcome, or response variable
• Independent and Dependent Variables:

  • Independent variable is manipulated and causes an effect
  • Dependent variable is measured and shows the effect of the independent variable
• Objective:

  • To determine the effect of bio-fertilizer "x" on plant growth
• Objective:

  • To determine if there is a relationship between students' characteristics and the time they spend online
• Descriptive Statistics - methods concerned with

  collecting, describing, and

  analyzing a set of data

  without drawing conclusions

  about a large group