[1 mark] Use Proc logistic to fit a logistic regression model that examines whether there is an association between high cholesterol (use high_CHOL as the response) and treatment for hypertension (use RXHYPER). Obtain the odds ratio and 95% confidence interval for high cholesterol comparing RXHYPER=yes vs no and provide an associated p-value. Write a sentence that includes and interprets these results.
[2 marks] Examine the relationship between high cholesterol (use high_CHOL as the response) and age (AGE) by using Proc logistic to fit a model that allows a quadratic relationship with AGE (i.e. include AGE and AGE*AGE).
Write down the algebraic representation of the fitted (i.e. with estimated coefficients) quadratic relationship. Provide evidence from your output as to whether you believe the relationship between high cholesterol and age is curved or straight. Also provide an interpretation of the relationship between high cholesterol and age using one or more odds ratios obtained from your fitted model that included the quadrat
ic term.
[2 marks] Use Proc logistic to investigate the relationship between high cholesterol and AGE that allows separate curved relationships with AGE for men and women.
Write down the algebraic representation of the fitted model separately for men and women. Perform (and interpret) a test of whether the curved relationship between AGE and high cholesterol is significantly different between men and women.
[1 mark] Obtain appropriate odds ratio estimates (using the fitted model in (c)) that compares high cholesterol between women and men at ages 40, 50, 60, and 70 years and provide an interpretation of these odds ratios in the context of the model fitted.
[1 mark] Use Proc logistic to fit a logistic regression model that examines the relationship between high cholesterol and RXHYPER, after adjustment for SEX and AGE (use your results from (b) and (c) to decide how to fully adjust for SEX and AGE). Describe how adjustment for SEX and AGE has changed your findings from (a) of the relationship between high cholesterol and RXHYPER.