Gerard E. Dallal, Ph.D Chief, Biostatistics Unit Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University 711 Washington Street Boston, MA 02111 Gerard.Dallal@tufts.edu
This invaluable text on the design and analysis of clinical research studies explains the basis of experimental design and statistics in a way that is sensitive to the clinical context in which nurses work....
“Confidence describes how narrow the confidence interval is (the narrower the better) around the effect of treatment, whether expressed as an absolute or relative risk reduction or as some other measure of efficacy. For readers still imprisoned by p values, this sort of "confidence" becomes greater as the p value becomes smaller.”
"we use inferential statistics to make inferences from our data to more general conditions; we use descriptive statistics simply to describe what's going on in our data."
“The Number Needed to Treat (NNT) is the number of patients you need to treat to prevent one additional bad outcome (death, stroke, etc.). For example, if a drug has an NNT of 5, it means you have to treat 5 people with the drug to prevent one additional bad outcome.”
“[Relative Risk] is a measure of association between exposure to a particular factor and risk of a certain outcome. The RR is defined to be the ratio of risk in the exposed and unexposed groups.