Error 1: Confusing p and q

Wrong: Using p for the recessive allele frequency. Correct: By convention, p = dominant allele frequency, q = recessive allele frequency. But in any problem, clearly define which is which from context. Prevention: Always check: $q^{2}$ = recessive PHENOTYPE frequency (the visible group that shows the recessive trait).

Error 2: Forgetting to Square Root $q^{2}$

Wrong: q = 0.16 (using $q^{2}$ directly as q). Correct: $q^{2}$ = 0.16, therefore q = √0.16 = 0.4 (take the square root). Prevention: The square root step is mandatory — never skip it.

Error 3: Using Phenotype Frequency as Allele Frequency

Wrong: Dominant phenotype frequency = 0.75, so p = 0.75. Correct: Dominant PHENOTYPE includes both AA ($p^{2}$) and Aa (2pq). Only $q^{2}$ directly gives an allele frequency without calculation. Prevention: Only $q^{2}$ directly converts to allele frequency by taking the square root.

Error 4: Thinking All Five H-W Conditions Must Be Violated Simultaneously

Wrong: "The population is in H-W equilibrium even though mutations occur, because there's no selection." Correct: H-W equilibrium requires ALL FIVE conditions simultaneously. Any single violation disrupts it. Prevention: Think of H-W as an "AND" condition — ALL five must be true.

Error 5: Interpreting Mutation "at a constant rate" as No Violation

Wrong: "Mutations occur at a constant rate, so the population stays in equilibrium." Correct: ANY mutation (any rate) disrupts H-W because new alleles are introduced. Only absolute zero mutations is compatible with H-W. Prevention: "No mutation" is the absolute condition, not "constant rate."

Error 6: Confusing Large Population with H-W Compliance

Wrong: "A large population is automatically in H-W equilibrium." Correct: Large population only satisfies the "no genetic drift" condition. The other four conditions must also be met. Prevention: List all five conditions explicitly for each scenario.