Hardy-Weinberg Problems -hw help. any help appreciated

[IluvChocolate]

Hi-

i have a series of simmilar problems such as this one and i could use some help as to how to go about doing this problem. i have read/studyed my notes, textbook etc. but i could use some extra help. if you know how to do/start this problem i would really appreciate it. thanks for taking your time to read this.

Problem:
4% of the newborn babies have sickle-cell anemia, (a recessive trait). Out of a random population of 1,000 babies, how many would you expect for each of the three possible genotypes?

My attempts/setting up the problem
The three possible genotypes
dominant
Hetrozygous
recessive

using the p+q=1.0 equation or the p^2+2pq+q^2=1.0
how do i apply the equation to the problem??
thanks

[blcr11]

They’ve given you q^2 = 0.04 (or p^2 = 0.04 if you prefer). Knowing that, you can calculate q. Knowing q you can calculate p. Once you know p and q, you know everything for a Hardy-Weinberg equilibrium. With my setup, q will be the frequency of the recessive allele while p will be the freqency of the dominant allele. The frequency of homozygous recessive individuals is q^2, homozygous dominant individuals is p^2, and of heterozygous individuals is 2pq. If you need the actual number of predicted individuals per 1000 with each genotype, then you need to multiply each of the genotypic frequencies by 1000.

[IluvChocolate]

thank you VERY much for helping me get started. i worked the problem through and got it right. thank you.