Research Methods in Psychology

Experimental Research

• Researchers actively manipulate conditions and observe in a controlled environment.
• Aims to determine if a specific treatment influences an outcome.
• True experiments involve random assignment of subjects to treatment conditions.
• Quasi experiments use non-randomized assignments of subjects.

Non-Experimental Research

• Researchers don't manipulate or control independent variables, typically conducted in natural settings.
• Types:
  • Comparative: tests differences between groups (e.g., comparing new vs. old curriculum)
  • Correlational: tests the strength of the relationship between variables (e.g., IQ and height)
  • Methodological: evaluates the effectiveness of a tool or questionnaire
  • Survey: examines characteristics of a population (e.g., school, community, social survey)

Quantitative Research

• Aims to find answers about relationships among measurable variables to explain, control, and predict phenomena.
• Emphasizes systematic procedures and brings order to complex data.
• Important considerations when conducting quantitative research:
  • Understanding the research problem
  • Understanding the nature of variables (categorical vs. metric data)
  • Determining the appropriate statistical procedures based on levels of measurement (NOIR: Nominal, Ordinal, Interval, Ratio)

Data Types in Quantitative Research

• Categorical Data: Cases are categorized with defined classes, often counted or yield frequencies. (e.g., gender: male, female).
• Metric Data: Cases are measured, resulting in metric or scale values. (e.g., height: 4.5m, IQ: 130)

Levels of Measurement (NOIR)

• Nominal: Categories with no specific order (e.g., gender, civil status, political affiliation).
• Ordinal: Categories imply ranking (e.g., year standing, ranks of professors, Likert scale).
• Interval: Difference between numbers has a known constant size, but zero is arbitrary (e.g., temperature in Celsius, IQ scores).
• Ratio: Highest level, has a fixed zero point, allowing for meaningful ratios (e.g., weight, height, income).

Measures of Central Tendency

• Mean: Average, calculated by adding all values and dividing by the number of values.
• Median: Value that divides the data set into two equal halves.
• Mode: Most frequently occurring value.

Descriptive Analysis

• Provides simple descriptions and summaries of the sample and observations.
• Includes measures of dispersion:
  • Range: Highest value - lowest value.
  • Variance: Average of the squares of the distances each value is from the mean.
  • Standard Deviation: Square root of the variance.

Measures of Association

• Phi Coefficient: Measures association for two binary variables (similar to Pearson correlation coefficient).
• Pearson R: Used for basic associational questions, indicates the strength and direction of a linear relationship between two metric variables.
• Multiple Regression: Used for complex multivariate associational questions, when predicting one variable based on multiple other variables.

Choosing the Appropriate Measure

• Univariate Analysis: Describing data with one variable: use measures of dispersion (range, variance, standard deviation) and measures of central tendency (mean, median, mode)
• Bivariate Analysis: Describing data with two variables, use measures of association depending on the nature of the data. For Nominal: Phi coefficient is adequate. For metric data, Pearson R is suitable.

Explore the different types of research methods used in psychology, including experimental and non-experimental designs. This quiz covers key concepts such as true experiments, quasi-experiments, and various non-experimental approaches like correlational and survey research. Test your understanding and application of these fundamental research techniques.