Gene and allele frequency, Chi squared test

This is the genetics question I need help with:   

One-thousand individuals were screened for their genotype at the MN blood group locus. The numbers of each genotype were:
MM   MN   NN
298   489   213
Assuming random mating, calculate the gene frequency for the M allele and the expected genotype frequencies. Use the chi-squared test to determine that mating is random.

Post Merge: 10 years ago

Here is what I have so far, but I do not understand how the Chi squared test works and can be used to determine mating randomness.

To calculate the frequency of each genotype, we take the frequency of each genotype and divide it by the number of individuals in the total population.  The frequency of MM is 0.298, MN is 0.489 and NN is 0.213, because these number are frequencies there sum should equal 1. 
To determine the frequency of the M allele we follow the same process and calculate the total number of alleles in the population, which would be 2000.  The genotype MM is homozygous, meaning that there are 2 M alleles present in each genotype.  The frequencies of M alleles present in each genotype are as follows: MM 596, MN 489 and NN 0.  The frequencies of N alleles present in each genotype are as follows: NN (homozygous) 426, MN 489, and MM 0.  To find the final allele frequencies of the population take the individual allele frequency and divide by 2000.  In the case of the M allele 1,085/2000 to equal 0.54, while the N allele is 0.46 and their sum equals 1.