Statistical Sciences 1023A/B Lecture Notes - Lecture 12: Contingency Table, Dependent And Independent Variables, Relative Risk

• School: Western University
• Department: Statistical Sciences
• Course: Statistical Sciences 1023A/B
• Professor: Lori Murray

Document Summary

Count the number of individuals who fall into each combination of categories. Present the counts in table = contingency table. A population contains 1000 individuals, of which 400 carry the gene for a disease. The proportion who carry the gene is . 40. The probability that someone carries the gene is 0. 40. The risk of carry the gene is 0. 40. The odds of carrying the gene are 4-6 (or 2-3 or 2/3 to 1) If placebo included, baseline risk = risk for placebo group. Relative risk: of outcome for two categories of explanatory variable is ratio of risks for each category. Relative risk of 3: risk of developing disease for one group is 3 ties what it is for another group. Relative risk of 1: risk is same for both categories of the explanatory variable (or both groups) Increased risk = (change in risk/baseline risk) x 100%