ANTC67H3 Lecture Notes - F-Test, Statistical Hypothesis Testing, Odds Ratio
Document Summary
How to do odd"s ratio: histogram, normal curve. It tells you what you achieved collectively on both points. Is the disease associated with exposure or is disease independent of exposure. Odd"s ratio: what is found in cell a and d decided by cell b and c, if it is close to 1 there is no association, so you want your odd"s ratio to be greater than 1. Null hypothesis (ho: drinking water and cholera are independent, lack of dependence. Alternative hypothesis (h1: they are dependent and associated. Null hypothesis is always one of no association. You are always looking at binary situation. Exposure to something will elevate the risk of cancer: lung cancer - smoking, breast cancer breast feed. Null hypothesis (condition and exposure have no effect on each other) Compute chi-square value: chi-sq tells you whether odd"s ratio is due to chance or not. So we reject hypothesis of null association.