Using Hardy- Weinberg Principle to calculate frequency of allele's! HELP please ! !?

http://anthro.palomar.edu/synthetic/synth_2.htm

FIrst make sure you know what frequency means. It means the amount of one color as compared to the others.  

Its been a while since I have used this.  The whole point to this principle is, and as an answer to your question c, whether the traits you see are due to RANDOM chance or are they due to some kind of selection taking place?  When no color of moth has a better chance of survival than any other, there will be an equilibrium (in frequencies) taking place because of the genes and allelles and the chances they have of meeting up with one another during reproduction are due to basically the flip of a coin (random chance)

When one color of moth is far more common than random gene mixing would predict, you can assume that there is something in the environment favoring that color.  In this case, the industrial center turned the trees dark, meaning that dark moths sitting on dark trees got eaten less by birds (probably).  EVen tho you can see from random areas (forest) the dark gene was recessive (i can tell just by looking because far fewer than half were black when radom gene mixing occured)

(p² + 2pq + q² = 1), p is defined as the frequency of the dominant allele and q as the frequency of the recessive allele for a trait controlled by a pair of alleles (A and a).   In other words, p equals all of the alleles in individuals who are homozygous dominant (AA) and half of the alleles in people who are heterozygous (Aa) for this trait in a population
p is the gene for LIGHT moth and q is the gene for DARK color.  Plug in your numbers for both cases (forest and then the industry)

Remember:  LIGHT moth may be pp or pq, since the light seems to be dominant
Dark moth can ONLY be qq (sort of like blue eyes vs. brown eyes in humans- the blue are recessive you have to have both recessives to show the blue trait, cannot carry brown recesively, like the moths cannot carry light color recessively)

It is assumed that the phenotype in greatest number is the dominant phenotype.  Therefore, in the upwind population, trhe dominant phenotype is light, which makes up 415/500 or 0.83 of the population; so, the dark phenotype makes up 0.17 of the population.  The frequency of the dark phenotype, ll, is 0.17, so the frequency of the l allele is sqrt(0.17) or 0.412;  the frequency of the L allele is 1-0.412 or 0.588.

In the downwind population the opposite is the case, but I'll use the same letters.  The frequency of the dark moths, ll,  is 210/300 or 0.7 of the population.  The frequency of the l allele in this populaiton is sqrt(0.7) or 0.837.  The frequency of the L allele is 1-0.837 or 0.163.

The reason for these differences in frequencies is that the L allele (light moths) is being selected AGAINST in the downwind population.