Unit 7 · Free note
Hardy–Weinberg in 3 steps
Do not take the square root of the dominant phenotype. AA and Aa are mixed, so that number is not p².
- Recessive phenotype frequency = q². Take the square root → q.
- p = 1 − q.
- Heterozygotes = 2pq. Homozygous dominant = p².
Chi-square vs Hardy–Weinberg: χ² = Σ (O−E)²/E. For df = 1, the critical value at p = 0.05 is 3.84. Larger → reject equilibrium.