Hardy Weinberg Equilibrium
The Hardy-Weinberg Equilibrium test checks whether observed genotype frequencies match expected frequencies for a population in genetic equilibrium.
Step 1 — Enter genotype counts
| Field | Represents |
|---|---|
| AA | Homozygous dominant |
| Aa | Heterozygous |
| aa | Homozygous recessive |
Also supports Excel upload and Sample Data Selector.
Step 2 — Calculate
Click Calculate Hardy-Weinberg Equilibrium.
Step 3 — Read the results
- Observed genotype counts (AA, Aa, aa, total N)
- Allele frequencies (p and q)
- Expected genotype counts under HWE
- Chi-square goodness-of-fit with df = 1 and p-value
- Equilibrium decision at alpha = 0.05
- Sample adequacy assessment
- Recommendations based on equilibrium status
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Statistical methods used
Allele frequencies
p = (2*AA + Aa) / (2N)q = (2*aa + Aa) / (2N)
Expected counts under HWE
- AA expected:
N * p^2 - Aa expected:
N * 2pq - aa expected:
N * q^2
Chi-square goodness-of-fit
chi2 = sum((observed - expected)^2 / expected) with df = 1.
Hypothesis statement
- H0: Population is in Hardy-Weinberg equilibrium
- H1: Population deviates from HWE
- alpha = 0.05
Sample adequacy
| Tier | Condition |
|---|---|
| Excellent | N >= 200 AND all expected >= 5 |
| Adequate | 100 <= N < 200 AND all expected >= 5 |
| Inadequate | N < 100 OR any expected < 5 |