MA

W1 - Intro Stats

Introduction to Behavioral Statistics

  • Scientific Method:
    • A process for gathering data and processing information.
    • Provides standardized steps for logical and rational problem-solving.
    • Importance: Helps in the gathering of scientific knowledge.

Statistics and Observations

  • Statistics:
    • Organizes and summarizes information.
    • Determines justified conclusions based on results obtained.
  • Goals of Statistical Procedures:
    • Accurate and meaningful interpretation of data.
    • Provides standardized evaluation procedures.

Populations and Samples

  • Population:
    • Set of all individuals of interest in a study.
    • Size can vary and is often large.
  • Sample:
    • A subset of individuals selected from a population.
    • Intended to represent the population in research.

Relationship between Population and Sample

  • The population includes all individuals of interest.
  • Results from the sample are generalized to the population.
  • The sample is selected from the population, ensuring representative data.

Parameters and Statistics

  • Parameter:
    • A value (usually numerical) describing a population.
    • Derived from measurements of individuals in the population.
  • Statistic:
    • A value (usually numerical) describing a sample.
    • Derived from measurements of individuals in the sample.

Variables and Data

  • Variable:
    • A characteristic or condition that has different values for different individuals.
  • Data:
    • Measurements or observations of a variable.
    • Data set: Collection of measurements or observations.
    • Datum: A single measurement or observation (commonly called a score or raw score).

Correlational Method

  • Involves one group of participants with two measured variables per individual.
  • Describes the type and magnitude of a relationship.
  • Limitations:
    • Does not provide an explanation for the existence of the relationship.
    • Does not demonstrate a cause-and-effect relationship between variables.

Experimental Method

  • Goal:
    • To determine cause-and-effect relationships.
  • Manipulation:
    • One variable's level is manipulated by the experimenter.
  • Independent Variable:
    • The variable manipulated by the researcher.
  • Dependent Variable:
    • The outcome measure assessed based on the treatment; its value depends on the independent variable.

Practice Question: Vitamin C and the Common Cold

  1. Researcher 1 uses interviews to determine vitamin C supplement use and records cold instances.
    • Type of Study: Non-experimental.
    • Reason: There is no manipulation of variables; it's observational.
  2. Researcher 2 divides students into two groups: one receiving vitamin C and the other not.
    • Type of Study: Experimental.
    • Reason: There is manipulation with the intent to determine the effect of vitamin C.

Variables

  • Discrete Variable:
    • Separate categories with no values in-between (e.g., types of transportation).
  • Continuous Variable:
    • Infinite possible values exist between two observed values (e.g., height, weight).

Scales of Measurement

  • Nominal Scale:
    • Categorizes and labels without quantitative distinctions.
    • Examples: Gender, diagnosis, experimental or control groups.
  • Ordinal Scale:
    • Ordered categories without consistent intervals.
    • Examples: Ranks, clothing sizes.
  • Interval Scale:
    • Ordered categories with equal intervals but no true zero point (e.g., temperature).
  • Ratio Scale:
    • Ordered categories with equal intervals and an absolute zero point (e.g., time to complete a task, number of correct answers).