Logic, Statistics, and Computer Science
What the exam tests
This domain tests propositional logic, argument analysis, basic statistics, and digital evidence. Questions are usually practical: identify a valid argument, compute a probability, or interpret a data set.
Core concepts
- Proposições e conectivos: negation, conjunction, disjunction, conditional, and biconditional; truth tables.
- Equivalências: p → q is equivalent to ¬q → ¬p (contrapositive) and to ¬p ∨ q.
- Argumentos válidos: modus ponens and modus tollens; fallacies of affirming the consequent and denying the antecedent.
- Estatística: mean, median, mode, standard deviation, and interpretation of graphs.
- Probabilidade: conditional probability and Bayes' theorem.
- Informática: digital evidence, hashing, and chain of custody for electronic data.
Traps
- Confusing the conditional with its converse; p → q does not imply q → p.
- Median vs. mean in skewed distributions; the mean is sensitive to outliers.
- Bayes: ignoring the base rate leads to the prosecutor's fallacy.
- Hash verifies integrity, not authorship.
Rule of thumb
For logic, translate the statement into symbols and test with a truth table or a counterexample. For statistics, always ask about the base rate and the denominator.
Worked example
A test detects a disease with 99% sensitivity and 99% specificity; prevalence is 1%. A positive result does not mean 99% probability of disease. Using Bayes, the posterior is about 50%. The exam tests whether you account for the base rate.