3.3: Deviations From Hardy-Weinberg

how to determine if population is in Hardy-Weinberg

1. calculate allele frequencies using population genotypes

2. use hardy-Weinberg equation to calculate expected genotype frequencies (null hypothesis)

3. apply chi-squared test

4. check X² value is significant

null hypothesis

Assumes there is no significant difference between observed and expected genotype frequencies in a population under Hardy-Weinberg equilibrium.

chi-squared test formula

X² = Σ((O - E)² / E)

O = observed frequency E = expected frequency

when is x² significant

When the p-value is less than 0.05 = reject null hypothesis = alleles are not in HW and 1 or more assumptions are not met - observed genotype frequencies differ significantly from expected frequencies.