Final answer:
The odds ratio for a SNP in a case/control study is calculated by organizing the data into a 2 x 2 contingency table and then using the formula (ad)/(bc), where 'a' is the number of cases with the SNP, 'b' is the number of cases without it, 'c' is the number of controls with it, and 'd' is the number of controls without it.
Step-by-step explanation:
To calculate the odds ratio of a SNP in a case/control study, you must first organize your data into a 2 x 2 contingency table. This table compares the presence and absence of the SNP in both cases and controls.
Odds ratio (OR) is calculated by taking the odds of exposure in cases (the odds that a case has the SNP) divided by the odds of exposure in controls (the odds that a control has the SNP). Mathematically, this is represented as:
OR = (ad) / (bc)
Where 'a' is the number of cases with the SNP, 'b' is the number of cases without the SNP, 'c' is the number of controls with the SNP, and 'd' is the number of controls without the SNP. Therefore, the correct answer and method to calculate the odds ratio for a SNP in a case/control study is neither of the options directly presented but rather involves the use of a contingency table and the formula given.