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Chapter 14: Quantitative Analysis: Descriptive Statistics - Coggle Diagram
Chapter 14: Quantitative Analysis: Descriptive Statistics
Introduction to Descriptive Statistics
Definition: Statistically describing, aggregating, and presenting constructs of interest or associations.
Contrast with Inferential Analysis: Focus on hypothesis testing.
Data Preparation
Handling Missing Values
Causes: Ambiguous or sensitive questions.
Strategies: Listwise deletion, imputation methods (maximum likelihood, multiple imputation).
Data Transformation
Examples: Reverse coding, creating scale measures, collapsing categories.
Data Entry
Methods: Spreadsheet, database, direct entry into statistical programs (SPSS, SAS).
Accuracy: Frequent checks, watch for obvious errors.
Data Coding
Codebook: Descriptions of variables, items, formats, response scales, coding values.
Example: Likert scale coding, nominal data coding, ratio scale data coding.
Process: Converting data into numeric format.
Univariate Analysis
Central Tendency
Measures: Mean (arithmetic, geometric, harmonic), median, mode.
Examples: Calculation of mean, median, mode with test scores.
Dispersion
Measures: Range, standard deviation.
Example: Sensitivity to outliers, formula for standard deviation.
Frequency Distribution
Definition: Summary of individual values or ranges.
Visualization: Bar charts, tables, normal distribution.
Examples and Applications
Hypothetical Dataset
Computation: Correlation value.
Table: Age and self-esteem.
Visual Comparisons
Figures: Histograms, correlation plots.
Interpretation: Positive, negative, or zero correlation.
Bivariate Analysis
Bivariate Correlation
Example: Age and self-esteem correlation.
Calculation: Formula, manual computation.
Definition: Relationship between two variables, strength of relationship.
Visualization: Histogram, scatter plot.
Significance Testing
Hypotheses: Null (H0) and alternative (H1).
Testing: One-tailed and two-tailed t-tests.
Statistical Testing: p-value, significance level (α), probabilistic nature.