Introduction.-1 Diagnostic Performance -- 1.1. The Results of an Examination Compared to a Reference Standard -- 1.2 Measures of Diagnostic Performance -- 1.3 Sensitivity, Specificity, FN Rate and FP Rate -- 1.4 Predictive Values, Diagnostic Accuracy, and Disease Prevalence -- 1.5 Bayes' Theorem, Likelihood Ratios, and Graphs of Conditional Probability -- 1.6 Cutoff and ROC Curves -- 2 Variables and Measurement Scales, Normal Distribution, and Confidence Intervals -- 2.1 Variables and Measurement Scales -- 2.2 Gaussian Distribution -- 2.3 Basics of Descriptive Statistics -- 2.4 Standard Error of the Mean -- 2.5 Standard Error of the Difference between two Sample Means -- 2.6 Confidence Intervals -- 2.7 Confidence Interval of a Proportion -- 3 Null Hypothesis, Statistical Significance and Power -- 3.1 Null hypothesis and Principle of Falsification -- 3.2 Cutoff for Significance, Type I or a Error and Type II or ß Error -- 3.3 Statistical Power -- 3.4 Why 0.05? -- 3.5 How to Read a p Value -- 4 Parametric Statistics -- 4.1 The Foundations of Parametric Statistics -- 4.2 Comparison Between Two Sample Means: Student's t Test -- 4.2.1 The Link with Confidence Intervals -- 4.3 Comparing Three or More Sample Means:the Analysis of Variance -- 4.4 Parametric Statistics in Radiology .-5 Non-Parametric Statistics -- 5.1 One Sample with Two paired Measurements -- 5.2. Two Independent Samples -- 5.3 Three or More (k) Dependent Samples -- 5.4 Three or More (k) Independent Samples -- 5.5 Some Considerations Regarding Non-Parametric Tests -- 6 Linear Correlation and Regression -- 6.1 Association and Causation -- 6.2 Correlation between Continuous Variables -- 6.3 Interpreting the Correlation Coefficient -- 6.4 Test for Significance -- 6.5 Rank Correlation -- 6.6 Linear Regression -- 6.7 Interpreting the Regression Line -- 6.8 Limitations of the Use of the Regression Line -- 7 Reproducibility: Intraobserver and Interobserver Variability -- 7.1 Sources of Variability -- 7.2 Why Do We Need to Know the Variability of Measurements? -- 7.3 Intraobserver and Interobserver Variability for Continuous Variables: the Bland-Altman Analysis -- 7.4 Interpreting the Results of the Bland-Altman Analysis -- 7.5 Intra- and Interobserver Variability for Categorical Variables: the Cohen k -- 8 Study Design, Systematic Reviews, and Levels of Evidence -- 8.1 Phases 1, 2, 3, and 4 of Pharmacologic Research -- 8.2 Study Classification -- 8.3 Experimental Studies and Control Group -- 8.4 Observational Studies -- 8.5 Randomized Controlled Studies: Alternative Approaches -- 8.6 Studies on Diagnostic Performance: Classification -- 8.7 Randomization and Minimization -- 8.8 Sample Size -- 8.9 Systematic Reviews (Meta-analyses) -- 8.10 Levels of Evidence -- 9 Bias in Studies on Diagnostic Performance -- 9.1 Classification -- 9.2 Bias Affecting External Validity -- 9.3 Bias Affecting Internal Validity -- 9.4 A Lot of Work to Be Done -- 10 How to Write a Radiologic Paper -- 10.1 Major Papers, Minor Papers, Invited Papers -- 10.2 Which Medical Journal? -- 10.3 Do We Always Need Institutional Review Board Approval and Informed Consent? -- 10.4 Title, Running Title and Title Page -- 10.5 Four-section Scheme, Section Size and Editing Sequence -- 10.6 «Introduction»: Why Did You Do It?- 10.7. «Materials and Methods»: What Did You Do and How Did You Do It?- 10.8 «Results»: What Did You Find?- 10.9 «Discussion»: What Is the Meaning of Your Findings?- 10.10 «References» -- 10.11 «Abstract» and «Keywords» -- 10.12 Shared Rules -- 10.13 Other Recommendations -- 10.14 Dealing with the Editor's Response and the Reviewers' Opinions -- 10.15 To Conclude -- Analytical and noun index.