Use a logistic model to assess the relationship between CIRSD and Depd, with Depd as the outcome variable.

(a) Write down the logistic model.

(b) Write down the null hypothesis that CIRSD has no effect.

(c) Write down the null hypothesis that there is no difference between CIRSD \(=1\) and CIRSD \(=2\).

(d) Test the null hypotheses in part

(b) and (c). Summarize your findings.