Biology
Hardy-Weinberg Lab Analysis Calculator
Derive observed allele frequency, generate expected genotype counts at the entered reference p, and expose the heterozygote difference and replicate-size context.
Observed sample size-
Observed allele A frequency-
Observed allele a frequency-
Expected AA count at reference p-
Expected heterozygous count at reference p-
Expected aa count at reference p-
Observed minus expected heterozygotes-
Average observations per replicate-
Decision view
Observed versus expected genotype composition
Observed versus expected genotype compositionObserved genotype counts establish the sample allele frequency before the selected reference p generates expected counts.
Exact scenario comparisonReference allele A frequency changes while all other entered assumptions remain constant.
| Reference allele A frequency | Observed sample size | Observed allele A frequency | Observed allele a frequency | Expected AA count at reference p | Expected heterozygous count at reference p | Expected aa count at reference p | Observed minus expected heterozygotes | Average observations per replicate |
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How to use Hardy-Weinberg Lab Analysis Calculator
- Verify genotype labels and sample size.
- Compare observed p with the entered reference p.
- Use a formal test when inference is required.
Calculator guide
Understanding Hardy-Weinberg Lab Analysis Calculator
A Hardy-Weinberg lab comparison begins with observed genotype counts and a clearly stated reference allele frequency.
Calculation method
How the calculation works
Derive the observed allele frequency from genotype counts and compare the complete observed sample with Hardy-Weinberg expectations at a selected reference frequency. Count two A alleles in AA and one in Aa, divide by twice the sample size, then apply p², 2p(1−p), and (1−p)² to the selected reference frequency.
Lab interpretation
Audit departures before assigning biology
A mismatch can arise from biology, sampling, or measurement.
Worked situations
Practical examples
- AA contributes two A alleles.
- Expected counts sum to sample size apart from rounding.
- Observed minus expected heterozygotes preserves direction.
Better inputs
Useful tips
- Check expected cell counts.
- Investigate genotyping error.
- Account for population structure and relatedness.
Before relying on the result
Limitations and common mistakes
- This is descriptive, not a chi-square or exact test.
- Selection, migration, mutation, structure, relatedness, multiple alleles, and ploidy are excluded.
- Replicates are summarized only by average size.
Reference
Key terms
- Observed p
- A-allele frequency derived from genotype counts.
- Expected heterozygotes
- 2p(1−p) multiplied by sample size.
- Reference p
- Entered allele frequency used for expected counts.
- Replicate
- Separately collected sample or experimental unit.
Important note
Calculated from the entered values using the displayed biological or statistical model. Study design, sampling, measurement quality, and biological variation affect interpretation.
Frequently asked questions
Does this test equilibrium?
No.
Why can observed p differ from reference p?
The reference is user-selected rather than fitted automatically.
Do expected counts sum to the sample?
Yes mathematically, subject to display rounding.
Are replicate counts analyzed separately?
No.