## HAP 719: Advanced Statistics I## Regression through Search
## Learning Objectives- Analyze data using search for key cases within the database
- Detect interactions among variables
- Estimate regression parameters for massive data without matrix manipulations
## Lecture- Interaction plots Slides► Video►
- Equation adjustments based on interaction plots Slides► Video►
- Estimating regression coefficients through search Slides► Video► YouTube►
## Assignments
Answer the following questions? - What is the approximate odds of mortality from stomach cancer? This estimate includes the average effect of comorbidities and cancer.
- For patients without cancer, which set of comorbidities has the highest risk of mortality?
- Does mortality from stomach cancer depend on medical history (comorbidities) of the patient?
- In strata 7, what is the impact of stomach cancer on mortality risk?
- In strata 20, what is the impact of stomach cancer on mortality risk?
- If we regress 6-month mortality on (a) stomach cancer and (b) combinations of comorbidities of patients, what is the approximate coefficient of stomach cancer in the regression equation? To answer this question, calculate the approximate change in mortality for change in occurrence of stomach cancer across all 31 strata.
- What is the coefficient associated with combination of cancer and medical history in strata 31?
- In what strata cancer adds the most to the risk of mortality?
- If we construct a linear regression model consisting of two variables, cancer and prognosis of patients associated with comorbidities captured in the strata, in which strata we are likely to have the highest residuals.
Resources for Corner Cases Question 1:
- What is the coefficient of X1 in the regression of Y on X1 through X4?
- What is the coefficient of X1X2 in the regression of logit of Y on X1 through X4 plus all possible interactions among independent variables?
- To get an exact specification of regression coefficient for X1, what do we need to do?
Resources for Corner Case Question 2: - Download data Excel►
- Using search technique what is the coefficient of the variable A?
- Using regression with no-intercept, what is the coefficient of the variable A?
- Create an interaction plot for variable A
Resources for Question 3 - Data Download►
- How to estimate coefficients of a variable through search Slides►
- Shreya Prasanna's answers YouTube►
- Interaction plot for variable A before sorting:
## MoreFor additional information (not part of the required reading), please see the following links: - Open introduction to statistics Read►
This page is part of the HAP 819 course on Advanced Statistics by Farrokh Alemi PhD Home► Email► |