Each question presents a biological research scenario. For each question, identify (a) the response variable and its specific type, (b) the explanatory variable and its specific type (if there is no explanatory variable, write "None"), (c) the type of inference (estimation or hypothesis testing) that most closely matches the goal of the analysis, and the target parameter(s) for that inference. Then (d) recommend the best option for an analytic method to make the inference, (e) list the conditions that must be met for the method to give valid results, and (f) identify a reasonable backup option that can be tried in case the assumptions cannot be met (more than one reasonable option may exist; you only need to identify one). Define any symbols that you use.

1. A researcher believes that a specific genetic mutation may be associated with a rare disease. To check, she samples 60 individuals who have the disease and 60 who do not, genotypes each of the 120 subjects to see if they have the mutation, and then tabulates the results.
2. Rice plants can absorb arsenic from the soil and incorporate it into their tissues, presenting a potential public health threat. To measure the relationship between soil arsenic concentration and arsenic concentrations in finished rice grains, 260 individual rice plants were randomly assigned to one of 26 soil arsenic concentrations ranging from 0 to 50 mg/kg (10 plants per concentration). After the plants had matured, arsenic concentrations were measured in 200 seeds from each plant and then averaged, yielding a single average tissue arsenic concentration per plant.