1. A researcher is studying the effect of factors that may contribute to a birth defect. The following is a table summarizing the results of bivariate and multivariate analysis.Table 1. Bivariate versus MultivariateVariable Crude OR 95% CI Adjusted OR 95% CIGene X 0.986 0.974–0.998 0.985 0.971–0.999Gene Y 4.317 1.916–9.727 3.430 1.377–8.547Gene Z 2.02 1.081–3.891 1.34 0.854–2.115Gene T 3.365 1.021–11.088 6.236 1.562–24.892A. Identify variables from Table 1 that should be further analyzed (to rule out whether they are confounders or effect modifiers). Briefly provide rationale.B. Stratified analysis was conducted on one of the genes in Table 1 and odds ratios were obtained. What do these results suggest:Drug A=0: OR=2.2 for birth defect given presence of geneDrug A=1: OR=1.4 for birth defect given presence of gene

2. Critically review the following controversial paper published (and later retracted) by Wakefield et al, which implicated MMR vaccine as a possible etiologic contributor to Autism, etc. You
may use either version for your review. Describe potential sources of bias and other limitations in the study: