Question

As you may recall from biostats we can never measure an entire population of interest, we only have sample data. This means that even if a population is at H-W equilibrium the genotype frequencies for a sample would almost never perfectly match the frequencies predicted from the allele frequencies. The X2 (chi-squared) statistical technique can be used to test observed deviations from expectation and determine whether the population is likely to be at H-W equilibrium or not. Consider the following data for a sample of 522 individuals collected from a population:

Genotype Number

AA 121
Aa 291
aa 110

Conduct a X2 test to determine if this data indicates that the population appears to be at H-W equilibrium based on this sample.

(a) What is the X2calc value you calculate for this data? X2calc. = ?(show all work, round to nearest 0.0001)

(b) Compare this to the appropriate critical values or use a statistical p = ?program to provide a range or exact value for the p value of your test.

(c) Interpret your results, would you conclude that this population is at H-W equilibrium or not? If not, what may be happening?

Answer 1

A) the X2 calculted is 53.3833

b) the exact p value of the test is <0.00001

c) Yes, the population is near to the H-W equilibrium because the p value at <0.05 level shows the non significance of the test.