Statistics fundamentals and key concepts

• Descriptive statistics summarize data using measures like mean, median and mode
• Inferential statistics make predictions or inferences about a population based on sample data
• A bar graph compares categories or discrete data
• A histogram displays the distribution of continuous data
• A line graph shows trends over time or ordered categories
• A scatterplot displays the relationship between two variables
• Mode is the most frequent value
• Median is the middle value when ordered
• Mean is the average of all values, often the most used
• Range is the difference between the highest and lowest values
• Variance is the average squared deviations from the mean
• Standard Deviation is the square root of variance, commonly used
• Correlation Coefficient measures the strength and direction of the relationship between two variables (range: -1 to +1)
• A correlation of -.45 indicates a moderate negative relationship
• A negative sign in correlation indicates an inverse relationship between variables
• Partial Correlation controls for one or more variables to see the relationship between two others
• Regression Analysis predicts the value of a dependent variable based on independent variables
• Simple Regression uses one IV, multiple Regression uses more than one
• Regression Equation predicts values of the dependent variable from independent variables
• Y-intercept is where the line crosses the Y-axis
• Regression Coefficient is the rate of change in the dependent variable for each unit change in the independent variable

Inferential Statistics

• The purpose is to make conclusions about populations from sample data
• Statistic describes a sample
• Parameter describes a population
• Sampling Distribution is the distribution of a statistic over repeated samples
• Standard Error is the standard deviation of a sampling distribution
• Null hypothesis: no effect or relationship
• Alternative hypothesis: there is an effect or relationship
• Significance Level is the probability threshold (usually 0.05) for rejecting the null hypothesis
• Type I Error: rejecting the null when it's true
• Type II Error: failing to reject the null when it's false
• Paired T-test compares the means of the same group at different times
• Independent T-test compares means of two different groups
• One-Way ANOVA compares means of more than two groups
• Null Hypothesis in ANOVA: no difference between group means
• Post Hoc Tests are done to identify which specific groups differ when ANOVA is significant
• Chi-Square Test is used for categorical data to test independence or goodness of fit

Scientific Research

• Scientific Method is based on evidence, experiments, and logical reasoning
• Method of Authority is based on expert knowledge
• Empirical Method is based on observation and experience
• Control in research ensures extraneous variables are kept constant
• Replicability ensures research findings are reliable when repeated
• Operationism defines concepts by how they are measured
• Meta-analysis combines data from multiple studies to establish more reliable conclusions
• Prediction hypothesizes future outcomes
• Explanation offers explanations for observed phenomena

Research Approaches & Methods of Data Collection

• Experimental Studies test cause-and-effect relationships by manipulating variables
• Independent Variable (IV): The variable being manipulated
• Dependent Variable (DV): The outcome measured
• Extraneous variables are not being studied but could influence results
• Correlational Research examines relationships between variables without manipulation
• Cross-Sectional Studies collect data at one point in time
• Longitudinal Studies collect data over time
• Qualitative Research focuses on understanding behavior and experiences in context

Ethical Issues in Research

• Beneficence and Nonmaleficence maximizes benefits, minimizing harm
• Fidelity and Responsibility maintains trust and integrity in research
• Justice ensures fairness in research
• Respect for People's Rights and Dignity acknowledges autonomy, privacy, and consent
• Informed Consent requires participants to understand the research and voluntarily agree to participate
• Deception is sometimes used when revealing the full nature of the study would alter results
• Debriefing explains the true nature of the study to participants after it's completed
• Institutional Review Board (IRB) ensures ethical standards are upheld in research involving humans

Research Design

• Control in experiments involves isolating the independent variable to determine cause and effect
• Causal Inference includes:
  • Causal Description: Identifying cause-effect relations
  • Causal Explanation: Explaining how or why a relationship exists

Survey Research

• Types of Surveys:
  • Cross-Sectional: Collects data at one point
  • Longitudinal: Collects data over time
  • Panel Study: Follows the same group over time
• Sampling Methods:
  • Random Sampling: Every participant has an equal chance of being selected
  • Convenience Sampling: Uses a readily available group of participants
• Survey Questions:
  • Closed-Ended: Fixed responses (e.g., yes/no)
  • Open-Ended: Allows detailed responses
  • Double-Barreled: Asks two questions at once (avoid this)
• Social Desirability Bias: Participants might answer questions in a way they think is socially acceptable

Qualitative Research

• Phenomenology focuses on understanding lived experiences
• Ethnography studies cultures and societies from an insider's perspective
• Case Studies are in-depth study of a single subject or a small group
• Reactivity occurs when participants change their behavior because they know they are being observed

Ethics in Research with Animals

• Ethical Principles for Animal Research:
  • Care and Housing: Animals must be treated humanely
  • Acquisition: Animals should be obtained ethically
  • Experimental Procedures: Minimizing harm in experiments