Psychological Research and Statistical Analysis Fundamentals

Correlation and Statistical Indices

• Positive Correlation: As one variable increases, the other also increases.
• Negative Correlation: As one variable increases, the other decreases.
• Correlation Coefficient: A statistical index of the relationship between two things, ranging from -1 to +1.

Measures of Central Tendency

A statistical measure that identifies a single value as representative of an entire distribution.

• Mean: The average of a set of numerical values.
• Median: The middle value in a list of numbers.
• Mode: The value that appears most often in a set of data.

Variation and Distribution

• Range: The difference between the highest and lowest values in a dataset.
• Standard Deviation: A measure of the amount of variation or dispersion in a set of values.
• Regression to the Mean: The phenomenon that if a variable is extreme on its first measurement, it will tend to be closer to the average on its second measurement.
• Positive Skew: A distribution where the curve is concentrated toward the left.
• Negative Skew: A distribution where the curve is concentrated toward the right.
• Percentile Rank: The percentage of scores in its frequency distribution that are equal to or lower than it.
• Bimodal Distribution: A distribution that shows two different peaks or modes in the frequency of occurrences.

Research Methodology

• Meta-Analysis: A statistical analysis that combines the results of multiple scientific studies.
• Empirical Evidence: Information acquired by observation or experimentation.
• Correlational Research: A non-experimental research method which studies the relationship between two variables with the help of statistical analysis.
• Statistical Significance: Tells us if the results of an experiment are true or if they occurred by chance (typically 0.05%).
• Operational Definition: Specific and measurable; defines how a variable will be quantified. It specifies tools, measurements, or methods used, which is central for replication and generalization.

The Five Research Methods (AAQ)

1. Examine: Experiment
2. Compare: Correlation
3. Closely: Case Study
4. Notice: Naturalistic Observation
5. Measure: Meta-analysis

Ethics in Research

• Institutional Review Boards (IRB): A committee that reviews and approves research involving human subjects, ensuring that ethical standards are met.
• Informed Consent: Permission granted with the knowledge of the possible consequences.